OpenGL Shaders. Pass array of float

Question

On my scene i have many objects that i want to rotate at the same time but on different angles.

I have a shader that computes position of each object and draw the whole scene (pass vertex array into the shader with array of vertexes).

    "uniform float uRotation;" +
    ...
    "   mat4 mz = mat4(1.0);" +
    "   mz[0][0] = cos(rotation);" +
    "   mz[0][1] = sin(rotation);" +
    "   mz[1][0] = -sin(rotation);" +
    "   mz[1][1] = cos(rotation);" +
    ...
    gl_Position = uMVPMatrix * (aPosition *mz);

i have all my vertexes, indexes, colors etc in arrays (not 1 array for each object, but 1 array with offset for vertexes, one for colors etc.).

I want to pass array of floats (angles for each "object") in one float[], but nothing is happinig.

    public void setRotations(float[] rotations)
    {
        GLES20.glUniform3fv(muRotation, rotations.length, rotations, 0);    
    }

if pass and use only one float everything is ok.

How can i pass specific float for each object (for example i want to draw 20 rectangles (i have a vetrex array: float[20*3*4]) as i understand i must have float for each vertex: rotations: float[20*4])?

UPDATED:

I try to pass array as a texture.

When i create resources for the scene - i try to create my array (called mask):

    mask = new float[512*512*4];
    for (int i = 0; i < mask.length; i++)
    {
        mask[i] = 2f;
    }

    GLES20.glActiveTexture(GLES20.GL_TEXTURE1);
    GLES20.glBindTexture(GLES20.GL_TEXTURE_2D, 1029384756);
    GLES20.glTexImage2D(GLES20.GL_TEXTURE_2D, 1, GLES20.GL_RGBA, 512, 512, 0, GLES20.GL_RGBA, GLES20.GL_FLOAT, FloatBuffer.wrap(mask));
    GLES20.glTexParameterf(GLES20.GL_TEXTURE_2D, GLES20.GL_TEXTURE_MIN_FILTER, GLES20.GL_LINEAR);
    GLES20.glActiveTexture(GLES20.GL_TEXTURE0);

Then when i draw new item on scene i use shader and try to pass my array:

    setShaderProgram(ShaderProgram.getInstance());

    GLES20.glActiveTexture(GLES20.GL_TEXTURE1);
    GLES20.glUniform1i(ShaderProgram.sUniformMask, GLES20.GL_TEXTURE1);
    GLES20.glBindTexture(GLES20.GL_TEXTURE_2D, 1029384756);
    GLES20.glActiveTexture(GLES20.GL_TEXTURE0);

But when i try to check any value from the array if it >0.5 every computation gives me false

UPDATED

Fragment shader contains:

"uniform sampler2D " + ShaderProgramConstants.UNIFORM_TEXTURE_0 + ";\n" +
"uniform sampler2D " + ShaderProgramConstants.UNIFORM_TEXTURE_1 + ";\n" +
"varying mediump vec2 " + ShaderProgramConstants.VARYING_TEXTURECOORDINATES + ";\n" +

"void main() {\n" +
"vec4 color = texture2D(" + ShaderProgramConstants.UNIFORM_TEXTURE_0 + ", " + ShaderProgramConstants.VARYING_TEXTURECOORDINATES + ");\n" +
"vec4 mask = texture2D(" + ShaderProgramConstants.UNIFORM_TEXTURE_1 + ", " + ShaderProgramConstants.VARYING_TEXTURECOORDINATES + ");\n" +
"float maskVal = mask.r;\n" ...

color and mask textures have the same dimensions

You can pass your array as a one dimensional texture.You can also pass a block of uniforms as UBO but it won't help you much if your array is big.The best way is to fill a texture and send it over. — Michael IV
– Michael IV, Commented Jul 16, 2012 at 12:53
I've already have textures for each element, i can't understand what do you mean. Maybe you have some links for good tutorials ? Thx. — dilix
– dilix, Commented Jul 17, 2012 at 8:46
In fact you should check if ES supports one dimensional textures.You your array values into glTexImage1D and use target of type GL_TEXTURE_1D.Then you can read it in the shader.I write it based on OpenGL desktop API.Check if you can do it in ES. — Michael IV
– Michael IV, Commented Jul 17, 2012 at 9:11
What are you doing in your shader. Do you have a Sampler2D and a texture coordinate to sample the texture? — Tim
– Tim, Commented Aug 14, 2012 at 4:42

Tim · Accepted Answer · 2012-08-10 15:59:54Z

3

+50

GLES20.glUniform1i(ShaderProgram.sUniformMask, GLES20.GL_TEXTURE1);

If this is your sampler uniform, it should read:

GLES20.glUniform1i(ShaderProgram.sUniformMask, 1); (not GL_TEXTURE1)

Similar for sampler0:

GLES20.glUniform1i(ShaderProgram.sUniformMask, 0);

answered Aug 10, 2012 at 15:59

Tim

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4 Comments

dilix Over a year ago

maybe smth like glGentexture is needed ?

dilix Over a year ago

There is an error 1282 (invalid operation) when i try to GLES20.glUniform1i(ShaderProgram.sUniformMask, 1);

Tim Over a year ago

@dilix Were you able to solve the error? Make sure your sUniformMask has a valid value, and that a valid shader is bound. There are several reasons why you can get an invalid operation, check the reasons at the bottom of this page

dilix Over a year ago

Yes, the trouble was i try to bid my unifore BEFORE i bin the fragment shader , thx =)

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