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Merge pull request #2984 from lilleyse/uniform-mediump
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Handle uniform precision mismatches
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@pjcozzi
pjcozzi committed Sep 1, 2015
2 parents fd81f3a + 2af0301 commit 29812e6
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Showing 5 changed files with 132 additions and 11 deletions.
5 changes: 5 additions & 0 deletions Source/Renderer/Context.js
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Original file line number Diff line number Diff line change
Expand Up @@ -259,6 +259,11 @@ define([
ContextLimits._maximumViewportWidth = maximumViewportDimensions[0];
ContextLimits._maximumViewportHeight = maximumViewportDimensions[1];

var highpFloat = gl.getShaderPrecisionFormat(gl.FRAGMENT_SHADER, gl.HIGH_FLOAT);
ContextLimits._highpFloatSupported = highpFloat.precision !== 0;
var highpInt = gl.getShaderPrecisionFormat(gl.FRAGMENT_SHADER, gl.HIGH_INT);
ContextLimits._highpIntSupported = highpInt.rangeMax !== 0;

this._antialias = gl.getContextAttributes().antialias;

// Query and initialize extensions
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27 changes: 26 additions & 1 deletion Source/Renderer/ContextLimits.js
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Original file line number Diff line number Diff line change
Expand Up @@ -27,7 +27,9 @@ define([
_maximumViewportHeight : 0,
_maximumTextureFilterAnisotropy : 0,
_maximumDrawBuffers : 0,
_maximumColorAttachments : 0
_maximumColorAttachments : 0,
_highpFloatSupported: false,
_highpIntSupported: false
};

defineProperties(ContextLimits, {
Expand Down Expand Up @@ -264,7 +266,30 @@ define([
get: function () {
return ContextLimits._maximumColorAttachments;
}
},

/**
* High precision float supported (<code>highp</code>) in fragment shaders.
* @memberof ContextLimits
* @type {Boolean}
*/
highpFloatSupported : {
get: function () {
return ContextLimits._highpFloatSupported;
}
},

/**
* High precision int supported (<code>highp</code>) in fragment shaders.
* @memberof ContextLimits
* @type {Boolean}
*/
highpIntSupported : {
get: function () {
return ContextLimits._highpIntSupported;
}
}

});

return ContextLimits;
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80 changes: 72 additions & 8 deletions Source/Renderer/ShaderProgram.js
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Original file line number Diff line number Diff line change
Expand Up @@ -2,21 +2,25 @@
define([
'../Core/defaultValue',
'../Core/defined',
'../Core/definedNotNull',
'../Core/defineProperties',
'../Core/destroyObject',
'../Core/DeveloperError',
'../Core/RuntimeError',
'./AutomaticUniforms',
'./ContextLimits',
'./createUniform',
'./createUniformArray'
], function(
defaultValue,
defined,
definedNotNull,
defineProperties,
destroyObject,
DeveloperError,
RuntimeError,
AutomaticUniforms,
ContextLimits,
createUniform,
createUniformArray) {
"use strict";
Expand All @@ -28,6 +32,8 @@ define([
* @private
*/
var ShaderProgram = function(options) {
var modifiedFS = handleUniformPrecisionMismatches(options.vertexShaderText, options.fragmentShaderText);

this._gl = options.gl;
this._logShaderCompilation = options.logShaderCompilation;
this._debugShaders = options.debugShaders;
Expand All @@ -40,6 +46,7 @@ define([
this._uniforms = undefined;
this._automaticUniforms = undefined;
this._manualUniforms = undefined;
this._duplicateUniformNames = modifiedFS.duplicateUniformNames;
this._cachedShader = undefined; // Used by ShaderCache

/**
Expand All @@ -50,7 +57,7 @@ define([
this._vertexShaderSource = options.vertexShaderSource;
this._vertexShaderText = options.vertexShaderText;
this._fragmentShaderSource = options.fragmentShaderSource;
this._fragmentShaderText = options.fragmentShaderText;
this._fragmentShaderText = modifiedFS.fragmentShaderText;

/**
* @private
Expand Down Expand Up @@ -127,6 +134,55 @@ define([
}
});

function extractUniforms(shaderText) {
var uniformNames = [];
var uniformLines = shaderText.match(/uniform.*?(?![^{]*})(?=[=\[;])/g);
if (definedNotNull(uniformLines)) {
var len = uniformLines.length;
for (var i = 0; i < len; i++) {
var line = uniformLines[i].trim();
var name = line.slice(line.lastIndexOf(' ') + 1);
uniformNames.push(name);
}
}
return uniformNames;
}

function handleUniformPrecisionMismatches(vertexShaderText, fragmentShaderText) {
// If a uniform exists in both the vertex and fragment shader but with different precision qualifiers,
// give the fragment shader uniform a different name. This fixes shader compilation errors on devices
// that only support mediump in the fragment shader.
var duplicateUniformNames = {};

if (!ContextLimits.highpFloatSupported || !ContextLimits.highpIntSupported) {
var i, j;
var uniformName;
var duplicateName;
var vertexShaderUniforms = extractUniforms(vertexShaderText);
var fragmentShaderUniforms = extractUniforms(fragmentShaderText);
var vertexUniformsCount = vertexShaderUniforms.length;
var fragmentUniformsCount = fragmentShaderUniforms.length;

for (i = 0; i < vertexUniformsCount; i++) {
for (j = 0; j < fragmentUniformsCount; j++) {
if (vertexShaderUniforms[i] === fragmentShaderUniforms[j]) {
uniformName = vertexShaderUniforms[i];
duplicateName = "czm_mediump_" + uniformName;
// Update fragmentShaderText with renamed uniforms
var re = new RegExp(uniformName + "\\b", "g");
fragmentShaderText = fragmentShaderText.replace(re, duplicateName);
duplicateUniformNames[duplicateName] = uniformName;
}
}
}
}

return {
fragmentShaderText : fragmentShaderText,
duplicateUniformNames : duplicateUniformNames
};
}

var consolePrefix = '[Cesium WebGL] ';

function createAndLinkProgram(gl, shader) {
Expand Down Expand Up @@ -346,20 +402,28 @@ define([
};
}

function partitionUniforms(uniforms) {
function partitionUniforms(shader, uniforms) {
var automaticUniforms = [];
var manualUniforms = [];

for ( var uniform in uniforms) {
for (var uniform in uniforms) {
if (uniforms.hasOwnProperty(uniform)) {
var automaticUniform = AutomaticUniforms[uniform];
if (automaticUniform) {
var uniformObject = uniforms[uniform];
var uniformName = uniform;
// if it's a duplicate uniform, use its original name so it is updated correctly
var duplicateUniform = shader._duplicateUniformNames[uniformName];
if (defined(duplicateUniform)) {
uniformObject.name = duplicateUniform;
uniformName = duplicateUniform;
}
var automaticUniform = AutomaticUniforms[uniformName];
if (defined(automaticUniform)) {
automaticUniforms.push({
uniform : uniforms[uniform],
uniform : uniformObject,
automaticUniform : automaticUniform
});
} else {
manualUniforms.push(uniforms[uniform]);
manualUniforms.push(uniformObject);
}
}
}
Expand Down Expand Up @@ -393,7 +457,7 @@ define([
var program = createAndLinkProgram(gl, shader, shader._debugShaders);
var numberOfVertexAttributes = gl.getProgramParameter(program, gl.ACTIVE_ATTRIBUTES);
var uniforms = findUniforms(gl, program);
var partitionedUniforms = partitionUniforms(uniforms.uniformsByName);
var partitionedUniforms = partitionUniforms(shader, uniforms.uniformsByName);

shader._program = program;
shader._numberOfVertexAttributes = numberOfVertexAttributes;
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3 changes: 3 additions & 0 deletions Source/Renderer/ShaderSource.js
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Original file line number Diff line number Diff line change
Expand Up @@ -14,6 +14,9 @@ define([
"use strict";

function removeComments(source) {
// remove inline comments
source = source.replace(/\/\/.*/g, '');
// remove multiline comment block
return source.replace(/\/\*\*[\s\S]*?\*\//gm, function(match) {
// preserve the number of lines in the comment block so the line numbers will be correct when debugging shaders
var numberOfLines = match.match(/\n/gm).length;
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28 changes: 26 additions & 2 deletions Specs/Renderer/ShaderProgramSpec.js
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Original file line number Diff line number Diff line change
Expand Up @@ -12,6 +12,7 @@ defineSuite([
'Renderer/Buffer',
'Renderer/BufferUsage',
'Renderer/ClearCommand',
'Renderer/ContextLimits',
'Renderer/DrawCommand',
'Renderer/ShaderSource',
'Renderer/VertexArray',
Expand All @@ -29,6 +30,7 @@ defineSuite([
Buffer,
BufferUsage,
ClearCommand,
ContextLimits,
DrawCommand,
ShaderSource,
VertexArray,
Expand Down Expand Up @@ -77,7 +79,7 @@ defineSuite([
}
});

function renderFragment(context, shaderProgram) {
function renderFragment(context, shaderProgram, uniformMap) {
va = new VertexArray({
context : context,
attributes : [{
Expand All @@ -97,7 +99,8 @@ defineSuite([
var command = new DrawCommand({
primitiveType : PrimitiveType.POINTS,
shaderProgram : shaderProgram,
vertexArray : va
vertexArray : va,
uniformMap : uniformMap
});
command.execute(context);

Expand Down Expand Up @@ -355,6 +358,27 @@ defineSuite([
expect(renderFragment(context, sp)).toEqual([255, 255, 255, 255]);
});

it('creates duplicate uniforms if precision of uniforms in vertex and fragment shader do not match', function() {
var highpFloatSupported = ContextLimits.highpFloatSupported;
ContextLimits._highpFloatSupported = false;
var vs = 'attribute vec4 position; uniform float u_value; varying float v_value; void main() { gl_PointSize = 1.0; v_value = u_value * czm_viewport.z; gl_Position = position; }';
var fs = 'uniform float u_value; varying float v_value; void main() { gl_FragColor = vec4(u_value * v_value * czm_viewport.z); }';
sp = ShaderProgram.fromCache({
context : context,
vertexShaderSource : vs,
fragmentShaderSource : fs
});
var uniformMap = {
u_value : function() {
return 1.0;
}
};
expect(sp.allUniforms.u_value).toBeDefined();
expect(sp.allUniforms.czm_mediump_u_value).toBeDefined();
expect(renderFragment(context, sp, uniformMap)).not.toEqual([0, 0, 0, 0]);
ContextLimits._highpFloatSupported = highpFloatSupported;
});

it('1 level function dependency', function() {
var vs = 'attribute vec4 position; void main() { gl_PointSize = 1.0; gl_Position = position; }';
var fs =
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