https://bugs.freedesktop.org/show_bug.cgi?id=44217
Bug #: 44217
Summary: vertex attribute 0 inconsistencies.
Classification: Unclassified
Product: Mesa
Version: git
Platform: x86-64 (AMD64)
OS/Version: Linux (All)
Status: NEW
Severity: normal
Priority: medium
Component: Mesa core
AssignedTo: mesa-dev@lists.freedesktop.org
ReportedBy: b...@taniwha.org
I was having a lot of trouble using glVertexAttrib4f to set the vertex color in
my shader, and I traced it down to it being due to the shader linker assigning
attribute 0 to my vcolor attribute.
There seem to be several problems related with vertex attribute 0:
The api test in get_current_attrib() is gles2 only, not gl3 as well (this may
be a misunderstanding on my part).
There are no api tests in VertexAttrib4fARB and friends (at least check for for
GLES2, please)
Most importantly: the shader linker is assigning attribute 0.
Interestingly, attribute 0 works perfectly well if an array is used on it.
I noticed the problem because when my vcolor attribute was assigned 0, it was
never set and thus everything was rendered black.
vertex shader
--8<--
uniform mat4 mvp_mat;
attribute vec4 vertex;
attribute vec4 vcolor;
varying vec4 color;
varying vec2 st;
void
main (void)
{
gl_Position = mvp_mat * vec4 (vertex.xy, 0.0, 1.0);
st = vertex.zw;
color = vcolor;
}
--8<--
fragment shader
--8<--
uniform sampler2D texture;
uniform sampler2D palette;
varying vec4 color;
varying vec2 st;
void
main (void)
{
float pix;
pix = texture2D (texture, st).r;
if (pix == 1.0)
discard;
gl_FragColor = texture2D (palette, vec2 (pix, 0.5)) * color;
}
--8<--
full source can be had from git://git.quakeforge.net/gitroot/quake/quakeforge
glsl branch. However, this has the workaround for the problem (vertex and
vcolor declaration order swapped in the vertex shader)
--
Configure bugmail: https://bugs.freedesktop.org/userprefs.cgi?tab=email
------- You are receiving this mail because: -------
You are the assignee for the bug.
_______________________________________________
mesa-dev mailing list
mesa-dev@lists.freedesktop.org
http://lists.freedesktop.org/mailman/listinfo/mesa-dev
