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ShaderBuilder / attempt to clarify the way attributes are handled in parseSymbolStyle

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This commit is contained in:
Olivier Guyot
2019-10-22 11:18:39 +02:00
parent 9ee93cd2cf
commit 7b66b294a8
1 changed files with 25 additions and 22 deletions
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47
src/ol/webgl/ShaderBuilder.js
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@@ -410,17 +410,20 @@ export function parseSymbolStyle(style) {
const offset = style.offset || [0, 0];
const opacity = style.opacity !== undefined ? style.opacity : 1;
const attributes = [];
const varyings = [];
function pA(value) {
return parse(value, attributes, 'a_');
const vertAttributes = [];
// parse function for vertex shader
function pVert(value) {
return parse(value, vertAttributes, 'a_');
}
function pV(value) {
return parse(value, varyings, 'v_');
const fragAttributes = [];
// parse function for fragment shader
function pFrag(value) {
return parse(value, fragAttributes, 'v_');
}
let opacityFilter = '1.0';
const visibleSize = pV(size[0]);
const visibleSize = pFrag(size[0]);
switch (style.symbolType) {
case 'square': break;
case 'image': break;
@@ -438,26 +441,26 @@ export function parseSymbolStyle(style) {
}
const builder = new ShaderBuilder()
.setSizeExpression(`vec2(${pA(size[0])}, ${pA(size[1])})`)
.setSymbolOffsetExpression(`vec2(${pA(offset[0])}, ${pA(offset[1])})`)
.setSizeExpression(`vec2(${pVert(size[0])}, ${pVert(size[1])})`)
.setSymbolOffsetExpression(`vec2(${pVert(offset[0])}, ${pVert(offset[1])})`)
.setTextureCoordinateExpression(
`vec4(${pA(texCoord[0])}, ${pA(texCoord[1])}, ${pA(texCoord[2])}, ${pA(texCoord[3])})`)
`vec4(${pVert(texCoord[0])}, ${pVert(texCoord[1])}, ${pVert(texCoord[2])}, ${pVert(texCoord[3])})`)
.setSymbolRotateWithView(!!style.rotateWithView)
.setColorExpression(`vec4(${pV(color[0])}, ${pV(color[1])}, ${pV(color[2])}, ${pV(color[3])})` +
` * vec4(1.0, 1.0, 1.0, ${pV(opacity)} * ${opacityFilter})`);
.setColorExpression(`vec4(${pFrag(color[0])}, ${pFrag(color[1])}, ${pFrag(color[2])}, ${pFrag(color[3])})` +
` * vec4(1.0, 1.0, 1.0, ${pFrag(opacity)} * ${opacityFilter})`);
// define the varyings that will be used to pass data from the vertex to the fragment shaders
// note: these should also be defined as attributes (if not already)
varyings.forEach(function(varyingName) {
if (attributes.indexOf(varyingName) === -1) {
attributes.push(varyingName);
// for each feature attribute used in the fragment shader, define a varying that will be used to pass data
// from the vertex to the fragment shader, as well as an attribute in the vertex shader (if not already present)
fragAttributes.forEach(function(attrName) {
if (vertAttributes.indexOf(attrName) === -1) {
vertAttributes.push(attrName);
}
builder.addVarying(`v_${varyingName}`, 'float', `a_${varyingName}`);
builder.addVarying(`v_${attrName}`, 'float', `a_${attrName}`);
});
// define the attributes from the features in the buffer
attributes.forEach(function(attributeName) {
builder.addAttribute(`float a_${attributeName}`);
// for each feature attribute used in the vertex shader, define an attribute in the vertex shader.
vertAttributes.forEach(function(attrName) {
builder.addAttribute(`float a_${attrName}`);
});
@@ -475,7 +478,7 @@ export function parseSymbolStyle(style) {
return {
builder: builder,
attributes: attributes.map(function(attributeName) {
attributes: vertAttributes.map(function(attributeName) {
return {
name: attributeName,
callback: function(feature) {