Shader Parser

[Mike Tajmajer]

Hi Petr,

I am slowly moving forward on the fragment parser/compiler.

I'm using the assumptions I made in the previous email.

[Mike Tajmajer]

Hi Petr,

This is accessing the framebuffer ;-)

It is as easy as it gets with the fragment shader.

My code is not pretty right now.

I am trying out things and there is much debugging code.

As I get parts working, I'll rewrite into something that is actually
useable.

Currently, I have most of a parser, and am creating the compiler -- it uses
AsmJit for this.

Here is my first sample. It uses a TEMP, modifies the TEMP, then writes it
to the framebuffer via result.color.

!!ARBfp1.0
TEMP color = {1, 0.5, -0.32, 1};
MOV color.r, -0.5;
MOV result.color, color;
END

The result is:

; Function Prototype:
; (int32)
;
; Variables:
; 0 int32 ( 4B) at dword ptr [ebp+8] - reg access: 9 , mem
access:
1
; 1 xmm_float4 (16B) at [None] - reg access: 4 , mem
access:
0
;
; Modified registers (2):
; GP :ecx
; MM :
; XMM:xmm0
L2:
push ebp
mov ebp, esp
L3:
; Initialize an XMM Register with a vector of 4 floats.
mov eax, 1065353216
mov ecx, dword ptr [ebp+8] ; alloc
mov dword ptr [ecx+32], eax
mov eax, 1056964608
mov dword ptr [ecx+36], eax
mov eax, -1096558838
mov dword ptr [ecx+40], eax
mov eax, 1065353216
mov dword ptr [ecx+44], eax
movaps xmm0, qword ptr [ecx+32]
; Update an XMM Register with a single float.
movaps qword ptr [ecx+32], xmm0
mov eax, -1090519040
mov dword ptr [ecx+32], eax
movaps xmm0, qword ptr [ecx+32]
; Copy an XMM Register to the result.color.
movaps qword ptr [ecx], xmm0
L4:
mov esp, ebp
pop ebp
ret
L1:
; Compiler successful (wrote 65 bytes).

[Mike Tajmajer]

Hi Petr,

I'm testing the MOV opcode with different data and it seems to be working OK
so far.

Next, I'm going to test using Cg to generate the ARB code -- then start
adding more OPcodes.

At that point, I can try connecting it to Fog.

For this, I will need a function to be called with the proposed pixel, and
to return the resulting pixel. Eventually I will need more info for the
context (x, y coords, etc.).

Working ARB Code:

!!ARBfp1.0
# Copy fragment.color to result.color;
MOV result.color, fragment.color;
END

!!ARBfp1.0
# Copy fragment.color to result.color
MOV result.color.r, fragment.color.r;
MOV result.color[1], fragment.color[1];
MOV result.color.ba, fragment.color.ba;
END

!!ARBfp1.0
TEMP color = {1.0, 2.0, 3.0, 4.0};
MOV result.color, color;
END

!!ARBfp1.0
TEMP color = {1.0, 2.0, 3.0, 4.0};
MOV result.color.r, color.r;
MOV result.color[1], color[1];
MOV result.color.ba, color.ba;
END

!!ARBfp1.0
MOV result.color.r, 1.0;
MOV result.color[1], 2.0;
MOV result.color.b, 3.0;
MOV result.color.a, 4.0;
END