Re: shader software emulation

Subject: Re: shader software emulation
From: Nick Burns <email@hidden>
Date: Fri, 11 Aug 2006 11:51:19 -0700
Delivered-to: email@hidden
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That shader does not compile for me...

When I fix it...
-----
attribute vec4 indices;
attribute vec3 weights;

uniform mat4 vertexMatrices[8];//fixed

void main(){

    int i0=int( indices.x );
    int i1=int( indices.y );
    int i2=int( indices.z );
    int i3=int( indices.w );

    float w0=weights.x;
    float w1=weights.y;
    float w2=weights.z;
    float w3=1.0-(w0+w1+w2);

	gl_Position = vec4(//fixed
        vertexMatrices[i0]*gl_Vertex*w0+
        vertexMatrices[i1]*gl_Vertex*w1+
        vertexMatrices[i2]*gl_Vertex*w2+
        vertexMatrices[i3]*gl_Vertex*w3 );
}
-----
This runs in HW on my quadro 4500 and x1600.

Can you send the exact shader source you are submitting to ogl + the source that does the submitting...

Also please test your shader in either Shader Builder or GLSLEditorSample (/Developer/Examples/OpenGL/Cocoa/GLSLEditorSample) or GLSLShowpiece (There is a vertex skinning example there that runs in hw.... however it draws a rather ugly alien...)

Hope this helps....

 - Nick

On Aug 10, 2006, at 5:02 PM, Mark Sibly wrote:

Hi,
I'm doing a bit of skinning in my vertex shader, something like....
[code]
attribute vec4 indices;
attribute vec3 weights;
uniform vertexMatrices:mat4[8]
void main(){
    int i0=int( indices.x );
    int i1=int( indices.y );
    int i2=int( indices.z );
    int i3=int( indices.w );
    float w0=weights.x;
    float w1=weights.y;
    float w2=weights.z;
    float w3=1.0-(w0+w1+w2);
    vec3 vertexPosition=(
        vertexMatrices[i0]*gl_Vertex*w0+
        vertexMatrices[i1]*gl_Vertex*w1+
        vertexMatrices[i2]*gl_Vertex*w2+
        vertexMatrices[i3]*gl_Vertex*w3 );
}
[/code]
Unfortunately, enabling this drops my framerate from 60FPS to around .5, so I assume it's triggering software emulation for some reason.

Does anyone know why, or perhaps of an alternative skining method that doesn't slow things down to sub-custard speed?

Could be instruction count I guess, but the rest of the shader isn't all that complex: my setup is an Intel iMac with RadeonX1600, theoertically quite a grunty card.
Bye!
Mark
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Follow-Ups:

Re: shader software emulation
From: Mark Sibly <email@hidden>


References:  
  >shader software emulation (From: Mark Sibly <email@hidden>)




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References:
	>shader software emulation (From: Mark Sibly <email@hidden>)