I am trying to apply both displacement mapping and specular mapping for the earth and only displacement mapping for the moon.
I could transfer height map to normal map but if I use the same height map to apply displacement mapping, it does not work as I expected..
Here is the example image
as you can see the bumpness around the earth and the moon but there are no actual height diffrences.
If I apply specular map to the earth, the earth becomes like this
I want only the ocean of the earth to shine but my code turns the earth into the whole black, I can only see some white dots on the earth...
These textures are from this site
Here is my both vertex shader code and the fragment shader code
"use strict";
const loc_aPosition = 3;
const loc_aNormal = 5;
const loc_aTexture = 7;
const VSHADER_SOURCE =
`#version 300 es
layout(location=${loc_aPosition}) in vec4 aPosition;
layout(location=${loc_aNormal}) in vec4 aNormal;
layout(location=${loc_aTexture}) in vec2 aTexCoord;
uniform mat4 uMvpMatrix;
uniform mat4 uModelMatrix; // Model matrix
uniform mat4 uNormalMatrix; // Transformation matrix of the normal
uniform sampler2D earth_disp;
uniform sampler2D moon_disp;
//uniform float earth_dispScale;
//uniform float moon_dispScale;
//uniform float earth_dispBias;
//uniform float moon_dispBias;
uniform bool uEarth;
uniform bool uMoon;
out vec2 vTexCoord;
out vec3 vNormal;
out vec3 vPosition;
void main()
{
float disp;
if(uEarth)
disp = texture(earth_disp, aTexCoord).r; //Extracting the color information from the image
else if(uMoon)
disp = texture(moon_disp, aTexCoord).r; //Extracting the color information from the image
vec4 displace = aPosition;
float displaceFactor = 2.0;
float displaceBias = 0.5;
if(uEarth || uMoon) //Using Displacement Mapping
{
displace += (displaceFactor * disp - displaceBias) * aNormal;
gl_Position = uMvpMatrix * displace;
}
else //Not using displacement mapping
gl_Position = uMvpMatrix * aPosition;
// Calculate the vertex position in the world coordinate
vPosition = vec3(uModelMatrix * aPosition);
vNormal = normalize(vec3(uNormalMatrix * aNormal));
vTexCoord = aTexCoord;
}`;
// Fragment shader program
const FSHADER_SOURCE =
`#version 300 es
precision mediump float;
uniform vec3 uLightColor; // Light color
uniform vec3 uLightPosition; // Position of the light source
uniform vec3 uAmbientLight; // Ambient light color
uniform sampler2D sun_color;
uniform sampler2D earth_color;
uniform sampler2D moon_color;
uniform sampler2D earth_bump;
uniform sampler2D moon_bump;
uniform sampler2D specularMap;
in vec3 vNormal;
in vec3 vPosition;
in vec2 vTexCoord;
out vec4 fColor;
uniform bool uIsSun;
uniform bool uIsEarth;
uniform bool uIsMoon;
vec2 dHdxy_fwd(sampler2D bumpMap, vec2 UV, float bumpScale)
{
vec2 dSTdx = dFdx( UV );
vec2 dSTdy = dFdy( UV );
float Hll = bumpScale * texture( bumpMap, UV ).x;
float dBx = bumpScale * texture( bumpMap, UV + dSTdx ).x - Hll;
float dBy = bumpScale * texture( bumpMap, UV + dSTdy ).x - Hll;
return vec2( dBx, dBy );
}
vec3 pertubNormalArb(vec3 surf_pos, vec3 surf_norm, vec2 dHdxy)
{
vec3 vSigmaX = vec3( dFdx( surf_pos.x ), dFdx( surf_pos.y ), dFdx( surf_pos.z ) );
vec3 vSigmaY = vec3( dFdy( surf_pos.x ), dFdy( surf_pos.y ), dFdy( surf_pos.z ) );
vec3 vN = surf_norm; // normalized
vec3 R1 = cross( vSigmaY, vN );
vec3 R2 = cross( vN, vSigmaX );
float fDet = dot( vSigmaX, R1 );
fDet *= ( float( gl_FrontFacing ) * 2.0 - 1.0 );
vec3 vGrad = sign( fDet ) * ( dHdxy.x * R1 + dHdxy.y * R2 );
return normalize( abs( fDet ) * surf_norm - vGrad );
}
void main()
{
vec2 dHdxy;
vec3 bumpNormal;
float bumpness = 1.0;
if(uIsSun)
fColor = texture(sun_color, vTexCoord);
else if(uIsEarth)
{
fColor = texture(earth_color, vTexCoord);
dHdxy = dHdxy_fwd(earth_bump, vTexCoord, bumpness);
}
else if(uIsMoon)
{
fColor = texture(moon_color, vTexCoord);
dHdxy = dHdxy_fwd(moon_bump, vTexCoord, bumpness);
}
// Normalize the normal because it is interpolated and not 1.0 in length any more
vec3 normal = normalize(vNormal);
// Calculate the light direction and make its length 1.
vec3 lightDirection = normalize(uLightPosition - vPosition);
// The dot product of the light direction and the orientation of a surface (the normal)
float nDotL;
if(uIsSun)
nDotL = 1.0;
else
nDotL = max(dot(lightDirection, normal), 0.0);
// Calculate the final color from diffuse reflection and ambient reflection
vec3 diffuse = uLightColor * fColor.rgb * nDotL;
vec3 ambient = uAmbientLight * fColor.rgb;
float specularFactor = texture(specularMap, vTexCoord).r; //Extracting the color information from the image
vec3 diffuseBump;
if(uIsEarth || uIsMoon)
{
bumpNormal = pertubNormalArb(vPosition, normal, dHdxy);
diffuseBump = min(diffuse + dot(bumpNormal, lightDirection), 1.1);
}
vec3 specular = vec3(0.0);
float shiness = 12.0;
vec3 lightSpecular = vec3(1.0);
if(uIsEarth && nDotL > 0.0)
{
vec3 v = normalize(-vPosition); // EyePosition
vec3 r = reflect(-lightDirection, bumpNormal); // Reflect from the surface
specular = lightSpecular * specularFactor * pow(dot(r, v), shiness);
}
//Update Final Color
if(uIsEarth)
fColor = vec4( (diffuse * diffuseBump * specular) + ambient, fColor.a); // Specular
else if(uIsMoon)
fColor = vec4( (diffuse * diffuseBump) + ambient, fColor.a);
else if(uIsSun)
fColor = vec4(diffuse + ambient, fColor.a);
}`;
Could you tell me where do I have to check?
If it was me I'd first strip the shader down the simplest thing and see if I get what I want. You want a specular shine so do you get a specular shine with only specular calculations in your shaders
Trimming your shaders to just draw a flat phong shading didn't produce the correct results
This line
fColor = vec4( (diffuse * specular) + ambient, fColor.a);
needed to be
fColor = vec4( (diffuse + specular) + ambient, fColor.a);
You add the specular, not multiply by it.
"use strict";
const loc_aPosition = 3;
const loc_aNormal = 5;
const loc_aTexture = 7;
const VSHADER_SOURCE =
`#version 300 es
layout(location=${loc_aPosition}) in vec4 aPosition;
layout(location=${loc_aNormal}) in vec4 aNormal;
uniform mat4 uMvpMatrix;
uniform mat4 uModelMatrix; // Model matrix
uniform mat4 uNormalMatrix; // Transformation matrix of the normal
out vec3 vNormal;
out vec3 vPosition;
void main()
{
gl_Position = uMvpMatrix * aPosition;
// Calculate the vertex position in the world coordinate
vPosition = vec3(uModelMatrix * aPosition);
vNormal = normalize(vec3(uNormalMatrix * aNormal));
}`;
// Fragment shader program
const FSHADER_SOURCE =
`#version 300 es
precision highp float;
uniform vec3 uLightColor; // Light color
uniform vec3 uLightPosition; // Position of the light source
uniform vec3 uAmbientLight; // Ambient light color
in vec3 vNormal;
in vec3 vPosition;
out vec4 fColor;
void main()
{
vec2 dHdxy;
vec3 bumpNormal;
float bumpness = 1.0;
fColor = vec4(0.5, 0.5, 1, 1);
// Normalize the normal because it is interpolated and not 1.0 in length any more
vec3 normal = normalize(vNormal);
// Calculate the light direction and make its length 1.
vec3 lightDirection = normalize(uLightPosition - vPosition);
// The dot product of the light direction and the orientation of a surface (the normal)
float nDotL;
nDotL = max(dot(lightDirection, normal), 0.0);
// Calculate the final color from diffuse reflection and ambient reflection
vec3 diffuse = uLightColor * fColor.rgb * nDotL;
vec3 ambient = uAmbientLight * fColor.rgb;
float specularFactor = 1.0;
bumpNormal = normal;
vec3 specular = vec3(0.0);
float shiness = 12.0;
vec3 lightSpecular = vec3(1.0);
vec3 v = normalize(-vPosition); // EyePosition
vec3 r = reflect(-lightDirection, bumpNormal); // Reflect from the surface
specular = lightSpecular * specularFactor * pow(dot(r, v), shiness);
fColor = vec4( (diffuse + specular) + ambient, fColor.a); // Specular
}`;
function main() {
const m4 = twgl.m4;
const gl = document.querySelector('canvas').getContext('webgl2');
if (!gl) { return alert('need webgl2'); }
const prgInfo = twgl.createProgramInfo(gl, [VSHADER_SOURCE, FSHADER_SOURCE]);
const verts = twgl.primitives.createSphereVertices(1, 40, 40);
// calls gl.createBuffer, gl.bindBuffer, gl.bufferData for each array
const bufferInfo = twgl.createBufferInfoFromArrays(gl, {
aPosition: verts.position,
aNormal: verts.normal,
aTexCoord: verts.texcoord,
indices: verts.indices,
});
// calls gl.bindBuffer, gl.enableVertexAttribArray, gl.vertexAttribPointer for each attribute
twgl.setBuffersAndAttributes(gl, prgInfo, bufferInfo);
twgl.resizeCanvasToDisplaySize(gl.canvas);
gl.clearColor(0, 0, 0, 1);
gl.clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT);
gl.enable(gl.DEPTH_TEST);
gl.enable(gl.CULL_FACE);
gl.viewport(0, 0, gl.canvas.width, gl.canvas.height);
gl.useProgram(prgInfo.program);
const fov = 60 * Math.PI / 180;
const aspect = gl.canvas.clientWidth / gl.canvas.clientHeight;
const near = 0.1;
const far = 20.0;
const mat = m4.perspective(fov, aspect, near, far);
m4.translate(mat, [0, 0, -3], mat);
// calls gl.activeTexture, gl.bindTexture, gl.uniform
twgl.setUniforms(prgInfo, {
uMvpMatrix: mat,
uModelMatrix: m4.identity(), // Model matrix
uNormalMatrix: m4.identity(), // Transformation matrix of the normal
uLightColor: [1, 1, 1], // Light color
uLightPosition: [2, 2, 10], // Position of the light source
uAmbientLight: [0, 0, 0], // Ambient light color
});
// calls gl.drawArrays or gl.drawElements
twgl.drawBufferInfo(gl, bufferInfo);
}
main();
body { margin: 0 }
canvas { display: block; width: 100vw; height: 100vh; }
<script src="https://twgljs.org/dist/4.x/twgl-full.min.js"></script>
<canvas></canvas>
So now we can add in the specular map
"use strict";
const loc_aPosition = 3;
const loc_aNormal = 5;
const loc_aTexCoord = 7;
const VSHADER_SOURCE =
`#version 300 es
layout(location=${loc_aPosition}) in vec4 aPosition;
layout(location=${loc_aNormal}) in vec4 aNormal;
layout(location=${loc_aTexCoord}) in vec2 aTexCoord;
uniform mat4 uMvpMatrix;
uniform mat4 uModelMatrix; // Model matrix
uniform mat4 uNormalMatrix; // Transformation matrix of the normal
out vec3 vNormal;
out vec3 vPosition;
out vec2 vTexCoord;
void main()
{
gl_Position = uMvpMatrix * aPosition;
// Calculate the vertex position in the world coordinate
vPosition = vec3(uModelMatrix * aPosition);
vNormal = normalize(vec3(uNormalMatrix * aNormal));
vTexCoord = aTexCoord;
}`;
// Fragment shader program
const FSHADER_SOURCE =
`#version 300 es
precision highp float;
uniform vec3 uLightColor; // Light color
uniform vec3 uLightPosition; // Position of the light source
uniform vec3 uAmbientLight; // Ambient light color
uniform sampler2D specularMap;
in vec3 vNormal;
in vec3 vPosition;
in vec2 vTexCoord;
out vec4 fColor;
void main()
{
vec2 dHdxy;
vec3 bumpNormal;
float bumpness = 1.0;
fColor = vec4(0.5, 0.5, 1, 1);
// Normalize the normal because it is interpolated and not 1.0 in length any more
vec3 normal = normalize(vNormal);
// Calculate the light direction and make its length 1.
vec3 lightDirection = normalize(uLightPosition - vPosition);
// The dot product of the light direction and the orientation of a surface (the normal)
float nDotL;
nDotL = max(dot(lightDirection, normal), 0.0);
// Calculate the final color from diffuse reflection and ambient reflection
vec3 diffuse = uLightColor * fColor.rgb * nDotL;
vec3 ambient = uAmbientLight * fColor.rgb;
float specularFactor = texture(specularMap, vTexCoord).r; //Extracting the color information from the image
bumpNormal = normal;
vec3 specular = vec3(0.0);
float shiness = 12.0;
vec3 lightSpecular = vec3(1.0);
vec3 v = normalize(-vPosition); // EyePosition
vec3 r = reflect(-lightDirection, bumpNormal); // Reflect from the surface
specular = lightSpecular * specularFactor * pow(dot(r, v), shiness);
fColor = vec4( (diffuse + specular) + ambient, fColor.a); // Specular
}`;
function main() {
const m4 = twgl.m4;
const gl = document.querySelector('canvas').getContext('webgl2');
if (!gl) { return alert('need webgl2'); }
const prgInfo = twgl.createProgramInfo(gl, [VSHADER_SOURCE, FSHADER_SOURCE]);
const verts = twgl.primitives.createSphereVertices(1, 40, 40);
// calls gl.createBuffer, gl.bindBuffer, gl.bufferData for each array
const bufferInfo = twgl.createBufferInfoFromArrays(gl, {
aPosition: verts.position,
aNormal: verts.normal,
aTexCoord: verts.texcoord,
indices: verts.indices,
});
const specularTex = twgl.createTexture(gl, {src: 'https://i.imgur.com/JlIJu5V.jpg'});
function render(time) {
twgl.resizeCanvasToDisplaySize(gl.canvas);
gl.clearColor(0, 0, 0, 1);
gl.clear(gl.COLOR_BUFFER_BIT | gl.DEPTH_BUFFER_BIT);
gl.enable(gl.DEPTH_TEST);
gl.enable(gl.CULL_FACE);
gl.viewport(0, 0, gl.canvas.width, gl.canvas.height);
// calls gl.bindBuffer, gl.enableVertexAttribArray, gl.vertexAttribPointer for each attribute
twgl.setBuffersAndAttributes(gl, prgInfo, bufferInfo);
gl.useProgram(prgInfo.program);
const fov = 60 * Math.PI / 180;
const aspect = gl.canvas.clientWidth / gl.canvas.clientHeight;
const near = 0.1;
const far = 20.0;
const mat = m4.perspective(fov, aspect, near, far);
m4.translate(mat, [0, 0, -3], mat);
const model = m4.rotationY(time / 1000);
m4.multiply(mat, model, mat);
// calls gl.activeTexture, gl.bindTexture, gl.uniform
twgl.setUniforms(prgInfo, {
uMvpMatrix: mat,
uModelMatrix: model, // Model matrix
uNormalMatrix: model, // Transformation matrix of the normal
uLightColor: [1, 1, 1], // Light color
uLightPosition: [2, 2, 10], // Position of the light source
uAmbientLight: [0, 0, 0], // Ambient light color
specularMap: specularTex,
});
// calls gl.drawArrays or gl.drawElements
twgl.drawBufferInfo(gl, bufferInfo);
requestAnimationFrame(render);
}
requestAnimationFrame(render);
}
main();
body { margin: 0 }
canvas { display: block; width: 100vw; height: 100vh; }
<script src="https://twgljs.org/dist/4.x/twgl-full.min.js"></script>
<canvas></canvas>
Then you should argably not use lots of boolean conditionals on your shader. Either make different shaders for find a way to do it without the booleans. So for example we don't need
uniform sampler2D earth_disp;
uniform sampler2D moon_disp;
uniform sampler2D sun_color;
uniform sampler2D earth_color;
uniform sampler2D moon_color;
uniform sampler2D earth_bump;
uniform sampler2D moon_bump;
uniform bool uIsSun;
uniform bool uIsEarth;
uniform bool uIsMoon;
we can just have
uniform sampler2D displacementMap;
uniform sampler2D surfaceColor;
uniform sampler2D bumpMap;
Then we can set the displacementMap and the bumpMap to a single pixel 0,0,0,0 texture and there will be no displacement and no bump.
As for different lighting for sun, given the sun uses neither the bump map nor the displacement map nor even lighting at all it would arguably be better to use a different shader but, we can also just add a maxDot value like this
uniform float maxDot;
...
nDotL = max(dot(lightDirection, normal), maxDot)
If maxDot is zero we'll get a normal dot product. If maxDot is one we get no lighting.
"use strict";
const loc_aPosition = 3;
const loc_aNormal = 5;
const loc_aTexture = 7;
const VSHADER_SOURCE =
`#version 300 es
layout(location=${loc_aPosition}) in vec4 aPosition;
layout(location=${loc_aNormal}) in vec3 aNormal;
layout(location=${loc_aTexture}) in vec2 aTexCoord;
uniform mat4 uMvpMatrix;
uniform mat4 uModelMatrix; // Model matrix
uniform mat4 uNormalMatrix; // Transformation matrix of the normal
uniform sampler2D displacementMap;
out vec2 vTexCoord;
out vec3 vNormal;
out vec3 vPosition;
void main()
{
float disp;
disp = texture(displacementMap, aTexCoord).r;
vec4 displace = aPosition;
float displaceFactor = 0.1;
float displaceBias = 0.0;
displace.xyz += (displaceFactor * disp - displaceBias) * aNormal;
gl_Position = uMvpMatrix * displace;
// Calculate the vertex position in the world coordinate
vPosition = vec3(uModelMatrix * aPosition);
vNormal = normalize(mat3(uNormalMatrix) * aNormal);
vTexCoord = aTexCoord;
}`;
// Fragment shader program
const FSHADER_SOURCE =
`#version 300 es
precision highp float;
uniform vec3 uLightColor; // Light color
uniform vec3 uLightPosition; // Position of the light source
uniform vec3 uAmbientLight; // Ambient light color
uniform sampler2D surfaceColor;
uniform sampler2D bumpMap;
uniform sampler2D specularMap;
uniform float maxDot;
in vec3 vNormal;
in vec3 vPosition;
in vec2 vTexCoord;
out vec4 fColor;
vec2 dHdxy_fwd(sampler2D bumpMap, vec2 UV, float bumpScale)
{
vec2 dSTdx = dFdx( UV );
vec2 dSTdy = dFdy( UV );
float Hll = bumpScale * texture( bumpMap, UV ).x;
float dBx = bumpScale * texture( bumpMap, UV + dSTdx ).x - Hll;
float dBy = bumpScale * texture( bumpMap, UV + dSTdy ).x - Hll;
return vec2( dBx, dBy );
}
vec3 pertubNormalArb(vec3 surf_pos, vec3 surf_norm, vec2 dHdxy)
{
vec3 vSigmaX = vec3( dFdx( surf_pos.x ), dFdx( surf_pos.y ), dFdx( surf_pos.z ) );
vec3 vSigmaY = vec3( dFdy( surf_pos.x ), dFdy( surf_pos.y ), dFdy( surf_pos.z ) );
vec3 vN = surf_norm; // normalized
vec3 R1 = cross( vSigmaY, vN );
vec3 R2 = cross( vN, vSigmaX );
float fDet = dot( vSigmaX, R1 );
fDet *= ( float( gl_FrontFacing ) * 2.0 - 1.0 );
vec3 vGrad = sign( fDet ) * ( dHdxy.x * R1 + dHdxy.y * R2 );
return normalize( abs( fDet ) * surf_norm - vGrad );
}
void main()
{
vec2 dHdxy;
vec3 bumpNormal;
float bumpness = 1.0;
fColor = texture(surfaceColor, vTexCoord);
dHdxy = dHdxy_fwd(bumpMap, vTexCoord, bumpness);
// Normalize the normal because it is interpolated and not 1.0 in length any more
vec3 normal = normalize(vNormal);
// Calculate the light direction and make its length 1.
vec3 lightDirection = normalize(uLightPosition - vPosition);
// The dot product of the light direction and the orientation of a surface (the normal)
float nDotL;
nDotL = max(dot(lightDirection, normal), maxDot);
// Calculate the final color from diffuse reflection and ambient reflection
vec3 diffuse = uLightColor * fColor.rgb * nDotL;
vec3 ambient = uAmbientLight * fColor.rgb;
float specularFactor = texture(specularMap, vTexCoord).r; //Extracting the color information from the image
vec3 diffuseBump;
bumpNormal = pertubNormalArb(vPosition, normal, dHdxy);
diffuseBump = min(diffuse + dot(bumpNormal, lightDirection), 1.1);
vec3 specular = vec3(0.0);
float shiness = 12.0;
vec3 lightSpecular = vec3(1.0);
vec3 v = normalize(-vPosition); // EyePosition
vec3 r = reflect(-lightDirection, bumpNormal); // Reflect from the surface
specular = lightSpecular * specularFactor * pow(dot(r, v), shiness);
//Update Final Color
fColor = vec4( (diffuse * diffuseBump + specular) + ambient, fColor.a); // Specular
}`;
function main() {
const m4 = twgl.m4;
const gl = document.querySelector('canvas').getContext('webgl2');
if (!gl) { return alert('need webgl2'); }
const prgInfo = twgl.createProgramInfo(gl, [VSHADER_SOURCE, FSHADER_SOURCE]);
const verts = twgl.primitives.createSphereVertices(1, 40, 40);
// calls gl.createBuffer, gl.bindBuffer, gl.bufferData for each array
const bufferInfo = twgl.createBufferInfoFromArrays(gl, {
aPosition: verts.position,
aNormal: verts.normal,
aTexCoord: verts.texcoord,
indices: verts.indices,
});
const textures = twgl.createTextures(gl, {
zero: { src: new Uint8Array([0, 0, 0, 0])},
earthSpecular: { src: 'https://i.imgur.com/JlIJu5V.jpg' },
earthColor: { src: 'https://i.imgur.com/eCpD7bM.jpg' },
earthBump: { src: 'https://i.imgur.com/LzFNOP8.jpg' },
sunColor: { src: 'https://i.imgur.com/gl8zBLI.jpg', },
moonColor: { src: 'https://i.imgur.com/oLiU4fm.jpg', },
moonBump: { src: 'https://i.imgur.com/bDnjW8C.jpg', },
});
function render(time) {
// calls gl.bindBuffer, gl.enableVertexAttribArray, gl.vertexAttribPointer for each attribute
twgl.setBuffersAndAttributes(gl, prgInfo, bufferInfo);
twgl.resizeCanvasToDisplaySize(gl.canvas);
gl.enable(gl.DEPTH_TEST);
gl.enable(gl.CULL_FACE);
gl.viewport(0, 0, gl.canvas.width, gl.canvas.height);
gl.useProgram(prgInfo.program);
const aspect = gl.canvas.clientWidth / gl.canvas.clientHeight;
const fov = 60 * Math.PI / 180 / aspect;
const near = 0.1;
const far = 20.0;
const viewProjection = m4.perspective(fov, aspect, near, far);
m4.translate(viewProjection, [0, 0, -6], viewProjection);
draw([0, 0, 0], {
displacementMap: textures.earthBump,
bumpMap: textures.earthBump,
surfaceColor: textures.earthColor,
specularMap: textures.earthSpecular,
maxDot: 0,
uAmbientLight: [0, 0, 0],
});
draw([-2.2, 0, 0], {
displacementMap: textures.zero,
bumpMap: textures.zero,
surfaceColor: textures.sunColor,
specularMap: textures.zero,
maxDot: 1,
uAmbientLight: [0, 0, 0],
});
draw([2.2, 0, 0], {
displacementMap: textures.moonBump,
bumpMap: textures.moonBump,
surfaceColor: textures.moonColor,
specularMap: textures.zero,
maxDot: 0,
uAmbientLight: [0, 0, 0],
});
function draw(translation, uniforms) {
const model = m4.translation(translation);
m4.rotateY(model, time / 1000, model);
// calls gl.activeTexture, gl.bindTexture, gl.uniform
twgl.setUniforms(prgInfo, {
uMvpMatrix: m4.multiply(viewProjection, model),
uModelMatrix: model, // Model matrix
uNormalMatrix: m4.transpose(m4.inverse(model)), // Transformation matrix of the normal
uLightColor: [1, 1, 1], // Light color
uLightPosition: [2, 2, 10], // Position of the light source
uAmbientLight: [1, 0, 0], // Ambient light color
});
twgl.setUniforms(prgInfo, uniforms);
// calls gl.drawArrays or gl.drawElements
twgl.drawBufferInfo(gl, bufferInfo);
}
requestAnimationFrame(render);
}
requestAnimationFrame(render);
}
main();
body { margin: 0 }
canvas { display: block; width: 100vw; height: 100vh; }
<script src="https://twgljs.org/dist/4.x/twgl-full.min.js"></script>
<canvas></canvas>
As for the displacement, displacement only works on vertices so you need a lot of vertices in your sphere to be able to see any displacement
As well there was an bug related to displacement. You're passing in normals as vec4 and this line
displace += (displaceFactor * disp - displaceBias) * aNormal;
Ends up adding a vec4 displacement. In other words let's say you started with an a_Position of vec4(1,0,0,1) which would be on the left side of the sphere. aNormal because you declared it as a vec4 is probably vec4(1,0,0,1) as well. Assuming you're actually passing it vec3 normal data via attributes from your buffer the default value for W is 1. Let's assume disp is 1, displaceFactor is 2 and displaceBias is 0.5 which is what you had. You end up wioth
displace = vec4(1,0,0,1) + (2 * 1 + 0.5) * vec4(1,0,0,1)
displace = vec4(1,0,0,1) + (1.5) * vec4(1,0,0,1)
displace = vec4(1,0,0,1) + vec4(1.5,0,0,1.5)
displace = vec4(2.5,0,0,2.5)
But you don't want W to be 2.5. One fix is to just use the xyz part of the normal.
displace.xyz += (displaceFactor * disp - displaceBias) * aNormal.xyz;
The more normal fix would be to only declare the normal attribute as vec3
in vec3 aNormal;
displace.xyz += (displaceFactor * disp - displaceBias) * aNormal;
In my example above the spheres are only radius = 1 so we only want adjust this displacement a little. I set displaceFactor to 0.1 and displaceBias to 0.
I am trying to use GLSL to implement a Harris Corner Detection. But it does not work properly(I am guessing). First off it doesn't detect all corners and it detects alot of points that are not corners, another big problem is that it the threshold is very specific for each image. Maybe that is normal with a Harris detector?
All help is appreciated.
Shader Passes:
1st: Standard passthrough.
2nd: I turn the image into a grayscale image.
3rd: Sobel filtering the image and passing the x, y gradient intensitys and the product of the xy intensitys.
uniform sampler2D texture;
varying vec2 vUV;
void main() {
vec2 uv = vUV;
// Offset used to get access to neighbours
float w = 1.0/800.0;
float h = 1.0/600.0;
vec3 temp;
vec3 sum = vec3(0.0);
// Sobel - Edge Detection
// y gradient
vec3 texel0 = texture2D(texture, uv + vec2(-w, h)).xyz;
vec3 texel1 = texture2D(texture, uv + vec2(-w, 0)).xyz;
vec3 texel2 = texture2D(texture, uv + vec2(-w, -h)).xyz;
vec3 texel6 = texture2D(texture, uv + vec2(w, h)).xyz;
vec3 texel7 = texture2D(texture, uv + vec2(w, 0)).xyz;
vec3 texel8 = texture2D(texture, uv + vec2(w, -h)).xyz;
vec3 vertEdge = 1.0 * texel0 + (2.0*texel1) + 1.0 * texel2 -
(1.0 * texel6 + (2.0*texel7) + 1.0 * texel8);
// x gradient
vec3 texe0 = texture2D(texture, uv + vec2(-w,h)).xyz;
vec3 texe1 = texture2D(texture, uv + vec2(0, h)).xyz;
vec3 texe2 = texture2D(texture, uv + vec2(w, h)).xyz;
vec3 texe6 = texture2D(texture, uv + vec2(-w,-h)).xyz;
vec3 texe7 = texture2D(texture, uv + vec2(0,-h)).xyz;
vec3 texe8 = texture2D(texture, uv + vec2(w,-h)).xyz;
vec3 horizEdge = 1.0 * texe0 + (2.0*texe1) + 1.0 * texe2 -
(1.0 * texe6 + (2.0*texe7) + 1.0 * texe8);
// Gradient intensity values
float iy = (vertEdge.r + vertEdge.g + vertEdge.b) /3.0;
float ix = (horizEdge.r + horizEdge.g + horizEdge.b) /3.0;
// Absolute to get negative values
iy = abs(iy);
ix = abs(ix);
float gradProcduct = ix * iy;
gl_FragColor = vec4(ix,iy,gradProcduct, 0.0);
Not the best looking code - just want it to work for now
4th and 5th: Standard Gaussian Blur
6th: Calculating Harris Response.
If it is a corner i paint that pixel in magenta.
void main() {
vec2 uv = vUV;
float w = 1.0/800.0;
float h = 1.0/600.0;
float threshold = 0.05;
vec4 gradientInfo = texture2D(texture, uv);
/************** Harris Reponse **********************
R is calculated as R = det(M)- K(Trace(M)) which leads to
R = Ix^2*Ix^y - Ixy^2-K(ix^2+iy^2)^2
Ix = X-gradient intesity
Iy = Y-gradient intesity
Ixy = product of the X- and Y-gradient intensities
*********************************************************/
float R = pow(gradientInfo.r,2.0)*pow(gradientInfo.g,2.0)
- pow(gradientInfo.b,2.0)
- threshold * pow((pow(gradientInfo.r,2.0)+pow(gradientInfo.g,2.0)),2.0);
vec4 test;
//if(R > 0.000000000005)
if(R > 0.0000000000750){
// Extremley small values, ugly soloution for now to be able to use R in maxSupress
test = vec4(1.0, 0.0, 1.0, R*1000000000.0);
}
else
test = vec4(vec3(gradientInfo.xyz),0.0);
gl_FragColor = vec4( test);
}
Results
Result on a simple square
Result on a more complex figure with the same R and Threshold
And the result when the response check is mulitplied by a 1000. Doesn't really seem to work.
Below is the code for the maximum supression.
void main() {
vec2 uv = vUV;
float vOffset = 1.0/800.0;
float hOffset = 1.0/600.0;
vec4 neighbourPixels[9];
vec3 result;
int check = 0;
vec3 previous = texture2D(texture2, uv).xyz;
vec4 current = texture2D(texture, uv);
float temp = current.a;
vec4 neighbourArray[25];
if(current.a > 0.0){
for(int i = -2; i<3;i++){
for(int j = -2; j<3;j++){
if(temp < texture2D(texture, vUV.xy+vec2(i,j)*vec2(vOffset,hOffset)).a ){
//result = vec3(1.0,0.0,1.0);
check = 1;
break;
}
}
if(check==1){
break;
}
}
if(check==1){
result = vec3(1.0,0.0,0.0);
}
else{
result = vec3(0.0,1.0,1.0);
}
}
else{
result = previous.xyz;
}
gl_FragColor = vec4( result, 0.0);
}
You need to look for local maxima in the Harris response, rather than just thresholding. Dilate the response with a 3x3 or 5x5 box, then find pixels whether original response and dilated version are equal.
I have a code where I receive YUV channels and I'm drawing them using OpenGLES. Basically, I have a shader that combines them together.
I would like to add a sharpen filter to the result (using the following example: http://igortrindade.wordpress.com/2010/04/23/fun-with-opengl-and-shaders/)
I'm not sure how to run another shader on the actual result (since I would like to run it after my previous shader combined all channels to a single frame).
My current code looks like that:
glUniform1i(texLum, 0);
glUniform1i(texU, 1);
glUniform1i(texV, 2);
glEnableVertexAttribArray(positionLoc);
glVertexAttribPointer(positionLoc,
4,
GL_FLOAT,
GL_FALSE,
0,
&vertices[0]);
glEnableVertexAttribArray(texCoordLoc);
glVertexAttribPointer(texCoordLoc,
2,
GL_FLOAT,
GL_FALSE,
0,
&texCoords[0]);
glDrawElements(GL_TRIANGLES, sizeof(indices)/sizeof(indices[0]), GL_UNSIGNED_BYTE, &indices[0]);
I guess I need to add the new shader right before the last line (glDrawElements), but I'm not sure how to call it.
My shader looks like this:
static char const *frag =
"uniform lowp sampler2D texLum; \n"
"uniform lowp sampler2D texU; \n"
"uniform lowp sampler2D texV; \n"
"varying mediump vec2 texCoordAtFrag; \n"
"void main() { \n"
" lowp float Y = texture2D(texLum, texCoordAtFrag).r; \n"
" lowp float U = texture2D(texU, texCoordAtFrag).r; \n"
" lowp float V = texture2D(texV, texCoordAtFrag).r; \n"
" lowp float R = 1.164 * (Y - 16.0 / 256.0) + 1.596 * (V - 0.5); \n"
" lowp float G = 1.164 * (Y - 16.0 / 256.0) - 0.813 * (V - 0.5) - 0.391 * (U - 0.5); \n"
" lowp float B = 1.164 * (Y - 16.0 / 256.0) + 2.018 * (U - 0.5); \n"
" gl_FragColor = vec4(R,G,B,1); \n"
"}\r\n";
static char const *vert =
"varying mediump vec2 texCoordAtFrag; \n"
"attribute vec4 Position; \n"
"attribute vec2 TexCoord; \n"
"void main() { \n"
" texCoordAtFrag = TexCoord; \n"
" gl_Position = Position; \n"
"}\r\n";
Where texLum,texU,texV are the textures holding the channels.
Sharpen is a convolution filter, so it reads nine input values to produce one output value. So if you have another shader that is supposed to occur before it and operates one pixel at a time, there'd be a decent argument for running them in two steps (YUV transformation first, sharpen second) so as to eliminate repeated calculations, even if it weren't also the easiest way to combine shaders as closed boxes.
If you want to combine them live, break the YUV transformation into a separate function and have the sharpen filter call that function instead of texture2D. The GL shader compiler doesn't have any sort of restriction on the number of source files you can link together to make a compiled program precisely so that you can follow the usual programming routes for function reuse.
If you'd prefer to run one then run the other then use an intermediate render-to-texture stage. Do the YUV transform, then switch buffers and use the output of that as the input to the sharpen.
In practice the former may actually be faster than the latter since a YUV transform is probably a fast operation (if it's YUV to RGB then it's one matrix multiplication, for example) whereas memory speed and the need to do quite a drastic change state can be quite expensive. You'd probably need to profile if performance is a concern.
EDIT: so, from your current main you could just adapt that to (typed here, as I go, please forgive errors):
"uniform lowp sampler2D texLum; \n"
"uniform lowp sampler2D texU; \n"
"uniform lowp sampler2D texV; \n"
"varying mediump vec2 texCoordAtFrag; \n"
"lowp vec4 yuvTexture2D(mediump vec2 coord) { \n"
" lowp float Y = texture2D(texLum, coord).r; \n"
" lowp float U = texture2D(texU, coord).r; \n"
" lowp float V = texture2D(texV, coord).r; \n"
" lowp float R = 1.164 * (Y - 16.0 / 256.0) + 1.596 * (V - 0.5); \n"
" lowp float G = 1.164 * (Y - 16.0 / 256.0) - 0.813 * (V - 0.5) - 0.391 * (U - 0.5); \n"
" lowp float B = 1.164 * (Y - 16.0 / 256.0) + 2.018 * (U - 0.5); \n"
" return vec4(R,G,B,1.0); \n"
"}\r\n
And then in your sharpen filter you'd substitute the call to texture2D(<whatever>, coord) with a call to yuvTexture2D(coord), having either included the fragment in the source listing for the sharpen shader or linked it into the program. With respect to switching to using a matrix approach, I guess you'd want (I'm going to format it other than as a string constant, for ease of typing):
uniform lowp sampler2D texLum;
uniform lowp sampler2D texU;
uniform lowp sampler2D texV;
varying mediump vec2 texCoordAtFrag;
const mediump mat4 yuvToRgb =
mat4( 1.164, 1.164, 1.164, -0.07884,
2.018, -0.391, 0.0, 1.153216,
0.0, -0.813, 1.596, 0.53866,
0.0, 0.0, 0.0, 1.0);
lowp vec4 yuvTexture2D(mediump vec2 coord) {
lowp vec4 yuv =
vec4(
texture2D(texLum, coord).r,
texture2D(texU, coord).r,
texture2D(texV, coord).r,
1.0)
return yuvToRgb * yuv;
}
How can I perform the following image processing tasks using OpenGL ES 2.0 shaders?
Colorspace transform ( RGB/YUV/HSL/Lab )
Swirling of the image
Converting to a sketch
Converting to an oil painting
I just added filters to my open source GPUImage framework that perform three of the four processing tasks you describe (swirling, sketch filtering, and converting to an oil painting). While I don't yet have colorspace transforms as filters, I do have the ability to apply a matrix to transform colors.
As examples of these filters in action, here is a sepia tone color conversion:
a swirl distortion:
a sketch filter:
and finally, an oil painting conversion:
Note that all of these filters were done on live video frames, and all but the last filter can be run in real time on video from iOS device cameras. The last filter is pretty computationally intensive, so even as a shader it takes ~1 second or so to render on an iPad 2.
The sepia tone filter is based on the following color matrix fragment shader:
varying highp vec2 textureCoordinate;
uniform sampler2D inputImageTexture;
uniform lowp mat4 colorMatrix;
uniform lowp float intensity;
void main()
{
lowp vec4 textureColor = texture2D(inputImageTexture, textureCoordinate);
lowp vec4 outputColor = textureColor * colorMatrix;
gl_FragColor = (intensity * outputColor) + ((1.0 - intensity) * textureColor);
}
with a matrix of
self.colorMatrix = (GPUMatrix4x4){
{0.3588, 0.7044, 0.1368, 0},
{0.2990, 0.5870, 0.1140, 0},
{0.2392, 0.4696, 0.0912 ,0},
{0,0,0,0},
};
The swirl fragment shader is based on this Geeks 3D example and has the following code:
varying highp vec2 textureCoordinate;
uniform sampler2D inputImageTexture;
uniform highp vec2 center;
uniform highp float radius;
uniform highp float angle;
void main()
{
highp vec2 textureCoordinateToUse = textureCoordinate;
highp float dist = distance(center, textureCoordinate);
textureCoordinateToUse -= center;
if (dist < radius)
{
highp float percent = (radius - dist) / radius;
highp float theta = percent * percent * angle * 8.0;
highp float s = sin(theta);
highp float c = cos(theta);
textureCoordinateToUse = vec2(dot(textureCoordinateToUse, vec2(c, -s)), dot(textureCoordinateToUse, vec2(s, c)));
}
textureCoordinateToUse += center;
gl_FragColor = texture2D(inputImageTexture, textureCoordinateToUse );
}
The sketch filter is generated using Sobel edge detection, with edges shown in varying grey shades. The shader for this is as follows:
varying highp vec2 textureCoordinate;
uniform sampler2D inputImageTexture;
uniform mediump float intensity;
uniform mediump float imageWidthFactor;
uniform mediump float imageHeightFactor;
const mediump vec3 W = vec3(0.2125, 0.7154, 0.0721);
void main()
{
mediump vec3 textureColor = texture2D(inputImageTexture, textureCoordinate).rgb;
mediump vec2 stp0 = vec2(1.0 / imageWidthFactor, 0.0);
mediump vec2 st0p = vec2(0.0, 1.0 / imageHeightFactor);
mediump vec2 stpp = vec2(1.0 / imageWidthFactor, 1.0 / imageHeightFactor);
mediump vec2 stpm = vec2(1.0 / imageWidthFactor, -1.0 / imageHeightFactor);
mediump float i00 = dot( textureColor, W);
mediump float im1m1 = dot( texture2D(inputImageTexture, textureCoordinate - stpp).rgb, W);
mediump float ip1p1 = dot( texture2D(inputImageTexture, textureCoordinate + stpp).rgb, W);
mediump float im1p1 = dot( texture2D(inputImageTexture, textureCoordinate - stpm).rgb, W);
mediump float ip1m1 = dot( texture2D(inputImageTexture, textureCoordinate + stpm).rgb, W);
mediump float im10 = dot( texture2D(inputImageTexture, textureCoordinate - stp0).rgb, W);
mediump float ip10 = dot( texture2D(inputImageTexture, textureCoordinate + stp0).rgb, W);
mediump float i0m1 = dot( texture2D(inputImageTexture, textureCoordinate - st0p).rgb, W);
mediump float i0p1 = dot( texture2D(inputImageTexture, textureCoordinate + st0p).rgb, W);
mediump float h = -im1p1 - 2.0 * i0p1 - ip1p1 + im1m1 + 2.0 * i0m1 + ip1m1;
mediump float v = -im1m1 - 2.0 * im10 - im1p1 + ip1m1 + 2.0 * ip10 + ip1p1;
mediump float mag = 1.0 - length(vec2(h, v));
mediump vec3 target = vec3(mag);
gl_FragColor = vec4(mix(textureColor, target, intensity), 1.0);
}
Finally, the oil painting look is generated using a Kuwahara filter. This particular filter is from the outstanding work of Jan Eric Kyprianidis and his fellow researchers, as described in the article "Anisotropic Kuwahara Filtering on the GPU" within the GPU Pro book. The shader code from that is as follows:
varying highp vec2 textureCoordinate;
uniform sampler2D inputImageTexture;
uniform int radius;
precision highp float;
const vec2 src_size = vec2 (768.0, 1024.0);
void main (void)
{
vec2 uv = textureCoordinate;
float n = float((radius + 1) * (radius + 1));
vec3 m[4];
vec3 s[4];
for (int k = 0; k < 4; ++k) {
m[k] = vec3(0.0);
s[k] = vec3(0.0);
}
for (int j = -radius; j <= 0; ++j) {
for (int i = -radius; i <= 0; ++i) {
vec3 c = texture2D(inputImageTexture, uv + vec2(i,j) / src_size).rgb;
m[0] += c;
s[0] += c * c;
}
}
for (int j = -radius; j <= 0; ++j) {
for (int i = 0; i <= radius; ++i) {
vec3 c = texture2D(inputImageTexture, uv + vec2(i,j) / src_size).rgb;
m[1] += c;
s[1] += c * c;
}
}
for (int j = 0; j <= radius; ++j) {
for (int i = 0; i <= radius; ++i) {
vec3 c = texture2D(inputImageTexture, uv + vec2(i,j) / src_size).rgb;
m[2] += c;
s[2] += c * c;
}
}
for (int j = 0; j <= radius; ++j) {
for (int i = -radius; i <= 0; ++i) {
vec3 c = texture2D(inputImageTexture, uv + vec2(i,j) / src_size).rgb;
m[3] += c;
s[3] += c * c;
}
}
float min_sigma2 = 1e+2;
for (int k = 0; k < 4; ++k) {
m[k] /= n;
s[k] = abs(s[k] / n - m[k] * m[k]);
float sigma2 = s[k].r + s[k].g + s[k].b;
if (sigma2 < min_sigma2) {
min_sigma2 = sigma2;
gl_FragColor = vec4(m[k], 1.0);
}
}
}
Again, these are all built-in filters within GPUImage, so you can just drop that framework into your application and start using them on images, video, and movies without having to touch any OpenGL ES. All the code for the framework is available under a BSD license, if you'd like to see how it works or tweak it.
You could start by checking out this list of shaders here. If you want to dig in a bit more, I'd recommend you check out the orange book found here.