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Cg program behaving weird.

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Hi, I have written a very simple fragment program for a general-purpose application. Here is the snippet of the Cg source code: ############################################### uniform samplerRECT MATexture : TEXUNIT0; uniform samplerRECT RPTexture : TEXUNIT1; float2 DecodeIndex (float Index, float2 TexSize) { float CONV_CONST; float normAddr1D; CONV_CONST = 1.0 / TexSize.x; normAddr1D = Index * CONV_CONST; return float2(frac (normAddr1D) * TexSize.x, normAddr1D); } // DecodeIndex float4 Traverse ( uniform samplerRECT TextureA : TEXUNIT2, float2 Index : TEXCOORD2, float2 GridIndex : TEXCOORD0, uniform float4 ParameterList ) : COLOR { // DECLARE VARIABLES float4 A; float4 MA; float4 RP; float2 R; float M; // FOR TESTING ONLY float4 d = float4(0, 0, 0, 0); float d2 = float(0); float d2sqrt = float(0); A = texRECT (TextureA, Index); R = float2 (0, 0); MA = texRECT (MATexture, R); GridIndex = DecodeIndex (MA.z, ParameterList.xy); MA = texRECT (MATexture, GridIndex); while (1 != MA.x) { if (M != MA.x) { } else { RP = texRECT (RPTexture, GridIndex); if (0 != (distance (A.yzw, RP.yzw))) { // FOR TESTING ONLY d = RP - A; d2 = pow (d.y, 2) + pow (d.z, 2) + pow (d.w, 2); d2 = d2 + 0.000625; d2sqrt = sqrt (d2); break; // FOR TESTING } } } return float4 (d2sqrt, d2, 0, 0); // return float4 (d2, d.y, d.z, d.w); } ############################################### Also here is the "first" fragment values for all the textures (in case you need it). MATexture = float4(0.142857, 0, 0, 2) RPTexture = float4(0, -0.172046, -0.483953, 0.097067) TextureA = float4(0, 0.021291, 0.053253, 0.077247) When I return the data as: "return float4 (d2, d.x, d.y, d.z);", the program returns proper values. However, when I try to return the data as : "return float4 (d2sqrt, d2, 0, 0);", the program returns garbage values. Both the values of d2sqrt and d2 are not correct. The values returned are junk if I try returning in any other format like "return float4 d2sqrt" or else. I am totally confused as to what is happening and why it it returning junk values when I try to output in a different way. Here is some information regarding my development environment. Platform and OS : IA32(AMD) and Linux RedHat 9.0 Cg Driver : Release from June 15, 2005 Cg Profile : fp40 Graphics Hardware and driver : Nvidia 6600GT and driver version - 1.0-7667 released on June 22, 2005. Please help. Thanks

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Cg has had many codegen bugs (and still has AFAIK).
You'd better get used to looking at the generated asm code :(
(the game I worked on was full Cg)

compare both generated code; they shouldn't be too different, so the error is likely to stand out.

Good Luck,
Janos

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Guest Anonymous Poster
Hi,

Quote:
Original post by JohnBolton
Perhaps the problem is that if and while are not supported on your hardware.


"if" and "while" statements are supported on the hardware.

- FMS

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