Sampler3D in iOS - ios

I have just include OpenGL ES 3.0 in my iOS app and it is working fine.
I have a working shader below:
#version 300 es
precision mediump float;
uniform sampler2D texSampler;
uniform float fExposure;
in vec2 fTexCoord;
in vec3 fColor;
out vec4 fragmentColor;
void main()
{
fragmentColor = texture(texSampler, fTexCoord) * vec4(fColor, 1.0) * fExposure;
}
Now, I want to use a sampler3D so I have:
#version 300 es
precision mediump float;
uniform sampler3D texSampler;
uniform float fExposure;
in vec3 fTexCoord;
in vec3 fColor;
out vec4 fragmentColor;
void main()
{
fragmentColor = texture(texSampler, fTexCoord) * vec4(fColor, 1.0) * fExposure;
}
and it doesn't compile. Also, I changed the vec2 texCoord to vec3 texCoord in the vertex shader.
Actually, sampler3D is not recognized, but as far as i know it exists in OpenGL ES 3.0.
Any ideas?

Similar to float, sampler3D does not have a default precision. Add this at the start of your fragment shader, where you also specify the default float precision:
precision mediump sampler3D;
Of course you can use lowp instead if that gives you sufficient precision.
The only sampler types that have a default precision in ES 3.0/3.1 are sampler2D and samplerCube (both default to lowp). For all others, the precision has to be specified either as a default precision, or as part of the variable declaration.

Related

WebGL shader checking status of texture sampler2D

I want to have prepared shader component (for multi sampler tex)
In my current state i use (activate and bind) only 2 texture image.
But this line :
gl_FragColor = textureColor + textureColor1 + textureColor2;
Makes trouble with my texture view as the texture I sample textureColor2 from is not bound.
In shaders its not possible to use console.log or any other standard debugging methods.I am interested to learn more about shaders but i am stuck.
Code :
...
precision mediump float;
varying vec2 vTextureCoord;
varying vec3 vLightWeighting;
uniform sampler2D uSampler;
uniform sampler2D uSampler1;
uniform sampler2D uSampler2;
uniform sampler2D uSampler3;
uniform sampler2D uSampler4;
uniform sampler2D uSampler5;
uniform sampler2D uSampler6;
uniform sampler2D uSampler7;
uniform sampler2D uSampler8;
uniform sampler2D uSampler9;
uniform sampler2D uSampler10;
uniform sampler2D uSampler11;
uniform sampler2D uSampler12;
uniform sampler2D uSampler13;
void main(void) {
vec4 textureColor = texture2D(uSampler, vec2(vTextureCoord.s, vTextureCoord.t));
vec4 textureColor1 = texture2D(uSampler1, vec2(vTextureCoord.s, vTextureCoord.t));
vec4 textureColor2 = texture2D(uSampler2, vec2(vTextureCoord.s, vTextureCoord.t));
// Need help here
gl_FragColor = textureColor + textureColor1 ;
//gl_FragColor = textureColor + textureColor1 + textureColor2;
//UPDATED QUESTION
if ( ${numTextures} == 1)
{
gl_FragColor = textureColor;
}
else if (${numTextures} == 2)
{
gl_FragColor = textureColor + textureColor1;
}
else if (${numTextures} == 3)
{
gl_FragColor = textureColor + textureColor1 + textureColor2;
}
// i use simple pragmatic if else for now .
// i pass value to the shader on load
// i still cant update shader in run time
///////////////////////////////////////
// This is segment of draw function :
for (var t=0;t<object.textures.length;t++) {
eval( " world.GL.gl.activeTexture(world.GL.gl.TEXTURE"+t+"); " )
world.GL.gl.bindTexture(world.GL.gl.TEXTURE_2D, object.textures[t]);
world.GL.gl.pixelStorei(world.GL.gl.UNPACK_FLIP_Y_WEBGL, false);
world.GL.gl.texParameteri(world.GL.gl.TEXTURE_2D, world.GL.gl.TEXTURE_MAG_FILTER, world.GL.gl.NEAREST);
world.GL.gl.texParameteri(world.GL.gl.TEXTURE_2D, world.GL.gl.TEXTURE_MIN_FILTER, world.GL.gl.NEAREST);
world.GL.gl.texParameteri(world.GL.gl.TEXTURE_2D, world.GL.gl.TEXTURE_WRAP_S, world.GL.gl.CLAMP_TO_EDGE);
world.GL.gl.texParameteri(world.GL.gl.TEXTURE_2D, world.GL.gl.TEXTURE_WRAP_T, world.GL.gl.CLAMP_TO_EDGE);
// -- Allocate storage for the texture
//world.GL.gl.texStorage2D(world.GL.gl.TEXTURE_2D, 1, world.GL.gl.RGB8, 512, 512);
//world.GL.gl.texSubImage2D(world.GL.gl.TEXTURE_2D, 0, 0, 0, world.GL.gl.RGB, world.GL.gl.UNSIGNED_BYTE, image);
//world.GL.gl.generateMipmap(world.GL.gl.TEXTURE_2D);
world.GL.gl.uniform1i(object.shaderProgram.samplerUniform, t);
}
...
Maybe in run time best way is to manipulate with object.textures array ?!
Finally :
Override shader with new flag
Compile shader
New material is updated
What are you trying to accomplish?
The normal way to use lots of textures is to use a texture atlas which is covered toward the bottom of this article
Otherwise, no there is no way to detect if a texture is loaded in the shader. You need to pass in your own flags. For example
uniform bool textureLoaded[NUM_TEXTURES];
or
uniform float textureMixAmount[NUM_TEXTURES];
I'd use a texture atlas though if I were you unless you really know you're doing something unique that actually needs 14 textures.
It's also common to generate shaders on the fly. Pretty much all game engines do this. Three.js does it as well. So rather than turn textures on and off, write some code that generates a shader for N textures. Then when you only have one texture generate a 1 texture shader, when you have 2 generate a 2 texture shader, etc. That's far more efficient for the GPU than having a 14 texture shader and trying to turn off 13 textures.
Example:
// note, I'm not recommending this shader, only showing some code
// that generates a shader
function generateShaderSrc(numTextures) {
return `
// shader for ${numTextures} textures
precision mediump float;
varying vec2 vTextureCoord;
varying vec3 vLightWeighting;
uniform sampler2D uSampler[${numTextures}];
uniform float uMixAmount[${numTextures}];
void main() {
vec4 color = vec4(0);
for (int i = 0; i < ${numTextures}; ++i) {
vec4 texColor = texture2D(uSampler[i], vTextureCoord);
color = mix(color, texColor, uMixAmount[i]);
}
gl_FragColor = color;
}
`;
}
log(generateShaderSrc(1));
log(generateShaderSrc(4));
function log(...args) {
const elem = document.createElement("pre");
elem.textContent = [...args].join(' ');
document.body.appendChild(elem);
}
That's a pretty simple example. Real shader generators often do a whole lot more string manipulation.
You should also be aware WebGL 1.0 only requires support for 8 texture units. According to webglstats about 15% of devices only support 8 texture units so you probably want to check how many texture units the user has and warn them your app is not going to work if they have less than your app needs.

Unity application crashes on iOS due to shader not compiled

I am trying to build my Unity 5.4.2f2 application for iOS. It is done with no compile errors. But when I try to run the application using Xcode 8.0, it immediately crashes and the debugger reports the following error.
Initialize engine version: 5.4.2f2 (b7e030c65c9b)
-------- Shader compilation failed
#version 100
#extension GL_EXT_frag_depth : enable
precision highp float;
uniform highp vec4 _ProjectionParams;
uniform highp vec4 _ZBufferParams;
uniform highp mat4 unity_CameraToWorld;
uniform highp mat4 _NonJitteredVP;
uniform highp mat4 _PreviousVP;
uniform highp sampler2D _CameraDepthTexture;
varying highp vec2 xlv_TEXCOORD0;
varying highp vec3 xlv_TEXCOORD1;
void main ()
{
highp vec4 tmpvar_1;
tmpvar_1 = texture2D (_CameraDepthTexture, xlv_TEXCOORD0);
mediump vec2 tmpvar_2;
highp vec4 tmpvar_3;
tmpvar_3.w = 1.0;
tmpvar_3.xyz = ((xlv_TEXCOORD1 * (_ProjectionParams.z / xlv_TEXCOORD1.z)) * (1.0/((
(_ZBufferParams.x * tmpvar_1.x)
+ _ZBufferParams.y))));
highp vec4 tmpvar_4;
tmpvar_4 = (unity_CameraToWorld * tmpvar_3);
highp vec4 tmpvar_5;
tmpvar_5 = (_PreviousVP * tmpvar_4);
highp vec4 tmpvar_6;
tmpvar_6 = (_NonJitteredVP * tmpvar_4);
highp vec2 tmpvar_7;
tmpvar_7 = (((tmpvar_5.xy / tmpvar_5.w) + 1.0) / 2.0);
highp vec2 tmpvar_8;
tmpvar_8 = (((tmpvar_6.xy / tmpvar_6.w) + 1.0) / 2.0);
tmpvar_2 = (tmpvar_8 - tmpvar_7);
mediump vec4 tmpvar_9;
tmpvar_9.zw = vec2(0.0, 1.0);
tmpvar_9.xy = tmpvar_2;
gl_FragDepthEXT = tmpvar_1.x;
gl_FragData[0] = tmpvar_9;
}
failed compiling:
fragment evaluation shader
WARNING: 0:4: extension 'GL_EXT_frag_depth' is not supported
ERROR: 0:38: Use of undeclared identifier 'gl_FragDepthEXT'
Note: Creation of internal variant of shader 'Hidden/Internal-MotionVectors' failed.
WARNING: Shader Unsupported: 'Hidden/Internal-MotionVectors' - Pass '' has no vertex shader
WARNING: Shader Unsupported: 'Hidden/Internal-MotionVectors' - Setting to default shader.
Xcode 8.0 contains OPenGL 2.0.
At the Unity forum people tell us that it should be fine for Unity 5.4. But it's not working for me. On Android devices my application runs quite OK.
Open Unity -> Edit -> Project settings -> Graphics
Then see Depth Normals under built-in shader setting and Choose option no Support
From Edit/Project Settings/Graphics can see always included shaders, see if its there
Or if you have 3D objects in scene, disable [ ] Motion Vectors from all the mesh renderers..
You can search in hierarchy to see all of them: t:meshrendere
For me it was the "Motion Vectors" setting (also under Edit/Project Settings/Graphics).
Reference:
https://forum.unity3d.com/threads/hidden-shader-motionvectors.431470/
this Blit shader crash is mostly because of texture compilation, IOs doesnot support dds format textures, if you are using dds textures, replace them with jpeg or any other supported extensions and it will build on IOS safely. worked for me:) after long research.

GLSL ES equivalent to OpenGL GLSL 'out' keyword?

I have a vertex shader which works fine on Windows with OpenGL. I want to use the same shader on an iPad which supports OpenGL ES2.0.
Compilation of the shader fails with:
Invalid storage qualifiers 'out' in global variable context
From what I have read, the 'out' keyword required GLSL 1.5 which the iPad won't support. Is there an equivalent keyword to 'out' that I can use to pass the color into my fragment shader?
attribute vec4 vPosition;
attribute vec4 vColor;
uniform mat4 MVP;
out vec4 pass_Color;
void main()
{
gl_Position = MVP * vPosition;
pass_Color = vColor;
}
This vertex shader is used by me to create gradient blends, so I'm assigning a color to each vertex of a triangle and then the fragment shader interpolates the color between each vertex. That's why I'm not passing a straight color directly into the fragment shader.
Solved! In GLSL ES 1.0 that I'm using, I need to use 'varying' instead of 'in' and 'out'. Here's the working shader:
attribute vec4 vPosition;
attribute vec4 vColor;
uniform mat4 MVP;
varying vec4 pass_Color;
void main()
{
gl_Position = MVP * vPosition;
pass_Color = vColor;
}

OpenGL ES 2.0 draw Fullscreen Quad very slow

When I'm rendering my content onto a FBO with a texture bound to it and then render this bound texture to a fullscreen quad using a basic shader the performance drops ridiculously.
For example:
Render to screen directly (with basic shader):
And when render to texture first, then render texture with fullscreen quad: (with same basic shader, would be something like blur or bloom normally):
Anyone got an idea how to speed this up? Since the current performance is not usable. Also I'm using GLKit for the basic OpenGL stuff.
Need to use precisions in places where it's needed.
lowp - for colors, textures coord, normals etc.
highp - for matrices and vertices/positions
Quick reference , check the range of precisions, on 3 page in "Qualifiers".
// BasicShader.vsh
precision mediump float;
attribute highp vec2 position;
attribute lowp vec2 texCoord;
attribute lowp vec4 color;
varying lowp vec2 textureCoord;
varying lowp vec4 textureColor;
uniform highp mat4 projectionMat;
uniform highp mat4 worldMat;
void main() {
highp mat4 worldProj = worldMat * projectionMat;
gl_Position = worldProj * vec4(position, 0.0, 1.0);
textureCoord = texCoord;
textureColor = color;
}
// BasicShader.fsh
precision mediump float;
varying lowp vec2 textureCoord;
varying lowp vec4 textureColor;
uniform sampler2D sampler;
void main() {
lowp vec4 Color = texture2D(sampler, textureCoord);
gl_FragColor = Color * textureColor;
}
This is very likely caused by ill-performant openGL ES API calls.
You should attach a real device and do an openGL ES frame capture. (It really needs a real device, the option for frame capture won't be available with a simulator).
The frame capture will indicate memory and other warnings along with suggestions to fix them alongside each API call. Step through these and fix each. The performance should improve considerably.
Here's a couple of references to get this done:
Debugging openGL ES frame
Xcode tools overview

OpenGL ES performance 2.0 vs 1.1 (iPad)

In my simple 2D game I have 2x framerate drop when using ES 2.0 implementation for drawing. Is it OK or 2.0 should be faster if used properly?
P.S. If you are interested in details. I use very simple shaders:
vertex program:
uniform vec2 u_xyscale;
uniform vec2 u_st_to_uv;
attribute vec2 a_vertex;
attribute vec2 a_texcoord;
attribute vec4 a_diffuse;
varying vec4 v_diffuse;
varying vec2 v_texcoord;
void main(void)
{
v_diffuse = a_diffuse;
// convert texture coordinates from ST space to UV.
v_texcoord = a_texcoord * u_st_to_uv;
// transform XY coordinates from screen space to clip space.
gl_Position.xy = a_vertex * u_xyscale + vec2( -1.0, 1.0 );
gl_Position.zw = vec2( 0.0, 1.0 );
}
fragment program:
precision mediump float;
uniform sampler2D t_bitmap;
varying lowp vec4 v_diffuse;
varying vec2 v_texcoord;
void main(void)
{
vec4 color = texture2D( t_bitmap, v_texcoord );
gl_FragColor = v_diffuse * color;
}
"color" is a mediump variable, due to the default precision that you specified. This forces the implementation to convert the lowp sampled result to mediump. It also requires that diffuse be converted to mediump to perform the multiplication.
You can fix this by declaring "color" as lowp.

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