Problems with ATI fragment shader

OpenGL OpenGL: Advanced Coding
1

glBeginFragmentShaderATI();
// Pass 0
glPassTexCoordATI (GL_REG_3_ATI, GL_TEXTURE3_ARB, GL_SWIZZLE_STR_ATI); // Assign Reg3 with Tex#3 unit

glColorFragmentOp1ATI (GL_MOV_ATI, GL_REG_3_ATI, GL_NONE, GL_NONE, GL_ZERO, GL_NONE, GL_NONE);// Move Zero for test

// Pass1
glSampleMapATI (GL_REG_3_ATI, GL_REG_3_ATI, GL_SWIZZLE_STR_ATI); // It Works similar to ‘glSampleMapATI (GL_REG_3_ATI, GL_TEXTURE3_ARB, GL_SWIZZLE_STR_ATI);’ call.
Why???

glColorFragmentOp1ATI (GL_MOV_ATI, GL_REG_0_ATI, GL_NONE, GL_NONE,
GL_REG_3_ATI, GL_NONE, GL_NONE);//Store result

2

Try this link…
http://www.opengl.org/discussion_boards/ubb/Forum3/HTML/006662.html

You get the same problems???

Dan

3

For some reason the MOV instruction is ignored if it’s the first instruction (a bug perhaps?).

If you change it to MUL and just multiply zero by zero, it’s still zero, so it will have the same result. Though the MOV should work.

4

Yeah, that’s exactly the same problem i got some weeks ago. If you added an alpha MOV after the color MOV, it worked, though. After i downloaded and installed the latest OpenGL driver it worked fine.

Y.

5

Here’s the code I tested with…
GLfloat purple[]={1.0f, 0.0f, 1.0f, 1.0f, ‘\0’};
glBeginFragmentShaderATI();
glSetFragmentShaderConstantATI(GL_CON_0_ATI, (GLfloat*)purple);
glPassTexCoordATI(GL_REG_0_ATI, GL_TEXTURE0_ARB, GL_SWIZZLE_STR_ATI);
glColorFragmentOp1ATI(GL_MOV_ATI, GL_REG_0_ATI, GL_NONE, GL_NONE, GL_ONE, GL_NONE, GL_NONE);
glAlphaFragmentOp1ATI(GL_MOV_ATI, GL_REG_0_ATI, GL_NONE, GL_ONE, GL_NONE, GL_NONE);
//Second Pass Start Here//
glPassTexCoordATI(GL_REG_0_ATI, GL_REG_0_ATI, GL_SWIZZLE_STR_ATI);
glColorFragmentOp1ATI(GL_MOV_ATI, GL_REG_0_ATI, GL_NONE, GL_NONE, GL_CON_0_ATI, GL_NONE, GL_NONE);
glAlphaFragmentOp1ATI(GL_MOV_ATI, GL_REG_0_ATI, GL_NONE, GL_ONE, GL_NONE, GL_NONE);
glEndFragmentShaderATI();

Using the 7.72 drivers (Catalyst)
I believe that the problem exists somewhere in the use of the second pass of a shader and the use of a MOV_ATI command in the first pass.
If I leave off the second pass of the shader, my objects all get rendered white like their supposed to be. When the
glPassTexCoordATI(GL_REG_0_ATI, GL_REG_0_ATI, GL_SWIZZLE_STR_ATI);
is run, it’s as though REG_0 never contained the 1’s to begin with, it’s like it has 0’s. Another MOV_ATI in the second pass doesn’t seem to have any problems, just in the first pass (and the glAlphaFragmentOp*ATI(…) commands don’t seem to help resolve it.) I’ve never been a fan of using the MOV_ATI command anyways, I’d say stay away from it as much as possible (why waste a whole fragment op on just moving data around?!) Do like what Ysaneya said, make sure you’ve got the latest drivers (although, these are the problems I’m having with the latest drivers .) Also, it never hurts to make sure you’ve checked the shader spec and made sure your #define’s are up to date.

Dan