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'm working on porting a ZUI from SVG over to WebGL for a few reasons, and I'd like to render a grid using a fragment shader.
Here's the basic effect I'm going for https://dl.dropboxusercontent.com/u/412963/steel/restel_2.mp4
I'd like to have a triangle that has thin, 1px lines every 10 units, and a thicker 2px line every 100 units (the units here being arbitrary but consistent with world-space, not screen-space).
Here's what I have so far, without the secondary thicker lines like in the video (note that this is literally a copy from my open buffer, and obviously isn't right):
Vertex Shader:
attribute vec3 aVertexPosition;
uniform mat4 uMVMatrix;
uniform mat4 uPMatrix;
varying float vX;
varying float vY;
void main(void) {
vX = aVertexPosition.x;
vY = aVertexPosition.y;
gl_Position = uPMatrix * uMVMatrix * vec4(aVertexPosition, 1.0);
}
Fragment Shader:
precision mediump float;
uniform vec2 resolution;
uniform float uZoomFactor;
varying float vX;
varying float vY;
void main(void) {
float distance = gl_FragCoord.z / gl_FragCoord.w;
float fuzz = 1.0 / distance;
float minorLineFreq;
if (distance > 10.0) {
minorLineFreq = 1.0;
} else if (distance > 5.0) {
minorLineFreq = 1.0;
} else {
minorLineFreq = 0.10;
}
float xd = mod(vX, minorLineFreq) * 88.1;
float yd = mod(vY, minorLineFreq) * 88.1;
if (xd < fuzz) {
gl_FragColor = vec4(0.0,0.0,0.0,1.0);
} else if (yd < fuzz) {
gl_FragColor = vec4(0.0,0.0,0.0,1.0);
} else {
gl_FragColor = vec4(1.0, 1.0, 1.0, 1.0);
}
}
It produces approximately the right image at a certain distance (but notice the banding effect where there's 2px lines instead of 1px):
Grid with banding
Zoomed in grid with unwanted thicker lines
So, how can I get a consistent grid, with 1px thick lines at every distance, all inside of a WebGL fragment shader?
I believe I've found an acceptable solution.
Using the following vertices (drawn in a triangle strip):
[ 1.0 1.0 0.0
-1.0 1.0 0.0
1.0 -1.0 0.0
-1.0 -1.0 0.0]
Vertex shader:
attribute vec4 aVertexPosition;
void main(void) {
gl_Position = aVertexPosition;
}
Fragment Shader:
precision mediump float;
uniform float vpw; // Width, in pixels
uniform float vph; // Height, in pixels
uniform vec2 offset; // e.g. [-0.023500000000000434 0.9794000000000017], currently the same as the x/y offset in the mvMatrix
uniform vec2 pitch; // e.g. [50 50]
void main() {
float lX = gl_FragCoord.x / vpw;
float lY = gl_FragCoord.y / vph;
float scaleFactor = 10000.0;
float offX = (scaleFactor * offset[0]) + gl_FragCoord.x;
float offY = (scaleFactor * offset[1]) + (1.0 - gl_FragCoord.y);
if (int(mod(offX, pitch[0])) == 0 ||
int(mod(offY, pitch[1])) == 0) {
gl_FragColor = vec4(0.0, 0.0, 0.0, 0.5);
} else {
gl_FragColor = vec4(1.0, 1.0, 1.0, 1.0);
}
}
Gives results (depending on the pitch and offset) like:
gl_FragCoord is already scaled to the render target resolution. So you can simply:
precision mediump float;
vec4 color = vec4(1.);
vec2 pitch = vec2(50., 50.);
void main() {
if (mod(gl_FragCoord.x, pitch[0]) < 1. ||
mod(gl_FragCoord.y, pitch[1]) < 1.) {
gl_FragColor = color;
} else {
gl_FragColor = vec4(0.);
}
}
https://glslsandbox.com/e#74754.0
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.