On 08/10/2010 12:11 PM, randrianas...@gmail.com wrote:
Hello all!
Today i dived into GLSL for first time, so sorry if i write something stupid.
One user at #radeon (nick<papillon81>) asked why some shade doesn't work.
Here is link to vertex shader as i saw it today:
http://mapserver.flightgear.org/git/gitweb.pl?p=fgdata;a=blob;f=Shaders/3dcloud.vert;h=135658ddb12c83e0652c85181f92575eeb06cf50;hb=HEAD
With unmodified Mesa master (after commit what enabled OpenGL 2.1/GLSL 1.20
for r600 in master) there was error:
------------------
Compiling VERTEX source:
1: // -*-C++-*-
2: #version 120
3:
4: varying float fogFactor;
5:
6: attribute vec3 usrAttr1;
7: attribute vec3 usrAttr2;
8:
9: float textureIndexX = usrAttr1.r;
10: float textureIndexY = usrAttr1.g;
11: float wScale = usrAttr1.b;
12: float hScale = usrAttr2.r;
13: float shade = usrAttr2.g;
14: float cloud_height = usrAttr2.b;
15:
16: void main(void)
17: {
18: gl_TexCoord[0] = gl_MultiTexCoord0 + vec4(textureIndexX,
textureIndexY, 0.0, 0.0);
19: vec4 ep = gl_ModelViewMatrixInverse * vec4(0.0,0.0,0.0,1.0);
20: vec4 l = gl_ModelViewMatrixInverse * vec4(0.0,0.0,1.0,1.0);
21: vec3 u = normalize(ep.xyz - l.xyz);
22:
23: // Find a rotation matrix that rotates 1,0,0 into u. u, r and w are
24: // the columns of that matrix.
25: vec3 absu = abs(u);
26: vec3 r = normalize(vec3(-u.y, u.x, 0));
27: vec3 w = cross(u, r);
28:
29: // Do the matrix multiplication by [ u r w pos]. Assume no
30: // scaling in the homogeneous component of pos.
31: gl_Position = vec4(0.0, 0.0, 0.0, 1.0);
32: gl_Position.xyz = gl_Vertex.x * u;
33: gl_Position.xyz += gl_Vertex.y * r * wScale;
34: gl_Position.xyz += gl_Vertex.z * w * hScale;
35: gl_Position.xyz += gl_Color.xyz;
36:
37: // Determine a lighting normal based on the vertex position from the
38: // center of the cloud, so that sprite on the opposite side of the
cloud to the sun are darker.
39: float n = dot(normalize(-gl_LightSource[0].position.xyz),
40: normalize(mat3x3(gl_ModelViewMatrix) * (-
gl_Position.xyz)));;
41:
42: // Determine the position - used for fog and shading calculations
43: vec3 ecPosition = vec3(gl_ModelViewMatrix * gl_Position);
44: float fogCoord = abs(ecPosition.z);
45: float fract = smoothstep(0.0, cloud_height, gl_Position.z +
cloud_height);
46:
47: // Final position of the sprite
48: gl_Position = gl_ModelViewProjectionMatrix * gl_Position;
49:
50: // Determine the shading of the sprite based on its vertical position
and position relative to the sun.
51: n = min(smoothstep(-0.5, 0.0, n), fract);
52: // Determine the shading based on a mixture from the backlight to the
front
53: vec4 backlight = gl_LightSource[0].diffuse * shade;
54:
55: gl_FrontColor = mix(backlight, gl_LightSource[0].diffuse, n);
56: gl_FrontColor += gl_FrontLightModelProduct.sceneColor;
57:
58: // As we get within 100m of the sprite, it is faded out. Equally at
large distances it also fades out.
59: gl_FrontColor.a = min(smoothstep(10.0, 100.0, fogCoord), 1 -
smoothstep(15000.0, 20000.0, fogCoord));
60: gl_BackColor = gl_FrontColor;
61:
62: // Fog doesn't affect clouds as much as other objects.
63: fogFactor = exp( -gl_Fog.density * fogCoord * 0.5);
64: fogFactor = clamp(fogFactor, 0.0, 1.0);
65: }
VERTEX glCompileShader "" FAILED
VERTEX Shader "" infolog:
Error: mat3x3: undeclared function name.
Compiling FRAGMENT source:
1: uniform sampler2D baseTexture;
2: varying float fogFactor;
3:
4: void main(void)
5: {
6: vec4 base = texture2D( baseTexture, gl_TexCoord[0].st);
7: vec4 finalColor = base * gl_Color;
8: gl_FragColor.rgb = mix(gl_Fog.color.rgb, finalColor.rgb,
fogFactor );
9: gl_FragColor.a = mix(0.0, finalColor.a, fogFactor);
10: }
11:
Linking osg::Program "" id=29 contextID=0
Program's vertex attrib binding 10, usrAttr1
Program's vertex attrib binding 11, usrAttr2
glLinkProgram "" FAILED
Program "" infolog:
linking with uncompiled shader
---------------------------------
so, we dived in and found few links with some similar-looking problems.
Topic at Flightgear forum:
http://www.flightgear.org/forums/viewtopic.php?f=6&t=2387&p=77851
Message in Mac-OpenGL list:
http://lists.apple.com/archives/mac-opengl/2010/Aug/msg00000.html
vdrift developer's forum:
http://vdrift.net/Forum/viewtopic.php?t=734
And finally after modifying shader it compiles sucessfully:
we changed line 40
from
normalize(mat3x3(gl_ModelViewMatrix) * (- gl_Position.xyz)));;
into
normalize(vec3(gl_ModelViewMatrix * vec4(- gl_Position.xyz,0.0))));;
i tried to make simple patch, but it FAIL with real testing.
The mat3x3, mat2x2 and mat4x4 type names were added in GLSL 1.20 but
it looks like I missed that in the glsl compiler.
Does the line above work if you change it to read:
normalize(mat3(gl_ModelViewMatrix) * (- gl_Position.xyz)));;
Patch was simple:
------------------------
diff --git a/src/mesa/slang/slang_typeinfo.c b/src/mesa/slang/slang_typeinfo.c
index d039a12..847e330 100644
--- a/src/mesa/slang/slang_typeinfo.c
+++ b/src/mesa/slang/slang_typeinfo.c
@@ -187,8 +187,11 @@ static const type_specifier_type_name
type_specifier_type_names[] = {
{"vec3", SLANG_SPEC_VEC3},
{"vec4", SLANG_SPEC_VEC4},
{"mat2", SLANG_SPEC_MAT2},
+ {"mat2x2", SLANG_SPEC_MAT2},
{"mat3", SLANG_SPEC_MAT3},
+ {"mat3x3", SLANG_SPEC_MAT3},
{"mat4", SLANG_SPEC_MAT4},
+ {"mat4x4", SLANG_SPEC_MAT4},
{"mat2x3", SLANG_SPEC_MAT23},
{"mat3x2", SLANG_SPEC_MAT32},
{"mat2x4", SLANG_SPEC_MAT24},
as GLSL spec says on page 20:
"mat3x3 same as a mat3" -
http://www.opengl.org/registry/doc/GLSLangSpec.Full.1.20.8.pdf
But because my patch fail - i guess i need add new type into slang_typeinfo.h
and then modify
slang_typeinfo.c with completely new type (for other matNxN [square] cases
too).
You'd also have to add mat2x2, mat3x3 and mat4x4 in the parser in
src/glsl/cl/
I understand all work now focused on glsl2 branch, but may be our work (if i
produce anything working) will be useful for 7.8 ?
Possibly. If you can come up with the complete solution/patch I'll
consider it for 7.8.x. Otherwise, I wouldn't worry about it too much
in light of the new glsl2 compiler.
-Brian
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