GLSL bypassing float array to uniform

Question

setShaders

    muOffsetHandle = getUniformLocation("offset");      
    muWeightHandle = getUniformLocation("weight");

useProgram

    GLES20.glUniform1fv(muOffsetHandle, 1, mOffset, 0);
    GLES20.glUniform1fv(muWeightHandle, 1, mWeight, 0);

vars

private int muOffsetHandle;
private int muWeightHandle;

protected float mOffset[] =new float[] {0.0f, 1.3f, 3.3f}; 
protected float mWeight[] =new float[] {0.2f, 0.3f, 0.3f};

FragmentShader

        "uniform float offset[3];\n" +
        "uniform float weight[3];\n" +

then trying to reach: weight[i]

I get this:

Shader log: 0:13: S0004: Member reference or swizzle attempted on non-structure and non-vector

line 13: tc += texture2D(uFrameBufferTexture, vTextureCoord[0].xy + vec2(0.0, offset[i])/uScreenHeight).rgb * weight[i];

(i = 0 to 2)

so my question: How to bypassing a float array to a uniform? float[3]

the code

protected static final String mFShader = 
        "precision mediump float;\n" +
        "varying vec2 vTextureCoord;\n" +
        "uniform float uTime;\n" +
        "uniform float uScreenWidth;\n" +
        "uniform float uScreenHeight;\n" +
        "uniform sampler2D uFrameBufferTexture;\n"+

        "uniform float offset[3];\n" +
        "uniform float weight[3];\n" +

        "void main() {\n"+
        "  vec3 tc = vec3(1.0, 0.0, 0.0);\n"+
        "  if (vTextureCoord[0].x<(uTime-0.01)) {\n"+
        "    tc = texture2D(uFrameBufferTexture, vTextureCoord[0].xy).rgb * weight[0];\n"+
        "    for (int i=1; i<3; i++) {\n"+
        "      tc += texture2D(uFrameBufferTexture, vTextureCoord[0].xy + vec2(0.0, offset[i])/uScreenHeight).rgb * weight[i];\n"+
        "      tc += texture2D(uFrameBufferTexture, vTextureCoord[0].xy - vec2(0.0, offset[i])/uScreenHeight).rgb * weight[i];\n"+
        "    }\n"+
        "  }\n"+
        "  else if (vTextureCoord[0].x>=(uTime+0.01)) {\n"+
        "    tc = texture2D(uFrameBufferTexture, vTextureCoord[0].xy).rgb;\n"+
        "  }\n"+
        "   gl_FragColor = vec4(tc, 1.0);\n"+
        "}\n";

tc += texture2D(uFrameBufferTexture, vTextureCoord[0].xy + vec2(0.0, offset[i])/uScreenHeight).rgb * weight[i]; — lacas
– lacas, Commented Jun 14, 2012 at 9:15

moonshadow · Accepted Answer · 2012-06-14 09:52:17Z

3

The problem isn't actually with weight or offset. The compiler is complaining that you say vTextureCoord[0].xy, but you declared vTextureCoord as varying vec2 vTextureCoord;.

Either declare vTextureCoord as an array, or don't say [0].

edited Jun 14, 2012 at 9:52

answered Jun 14, 2012 at 9:24

moonshadow

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1 Comment

moonshadow Over a year ago

varying vec2 vTextureCoord[1]; (or whatever you need instead of 1)

dragostis · Accepted Answer · 2012-06-14 11:58:20Z

1

You don't need to declare it as an array, but if you want you can simply use:

varying vec4 vTextureCoord[3]; // you can use anything you want between the brackets

Also, don't forget to modify the varying the the vertex shader too so that they will be identical.

answered Jun 14, 2012 at 11:58

dragostis

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