Mesa (gallium-mesa-7.4): mesa: fix GLSL issue preventing use of all 16 generic vertex attributes
Alan Hourihane
alanh at kemper.freedesktop.org
Tue Feb 24 10:44:30 UTC 2009
Module: Mesa
Branch: gallium-mesa-7.4
Commit: 3511442e4384db0a9f4383cd64e1c8c1de61c5bb
URL: http://cgit.freedesktop.org/mesa/mesa/commit/?id=3511442e4384db0a9f4383cd64e1c8c1de61c5bb
Author: Brian Paul <brianp at vmware.com>
Date: Thu Feb 19 17:01:17 2009 -0700
mesa: fix GLSL issue preventing use of all 16 generic vertex attributes
Only 15 actually worked before since we always reserved generic[0] as an
alias for vertex position.
The case of vertex attribute 0 is tricky. The spec says that there is no
aliasing between generic vertex attributes 0..MAX_VERTEX_ATTRIBS-1 and the
conventional attributes. But it also says that calls to glVertexAttrib(0, v)
are equivalent to glVertex(v). The distinction seems to be in glVertex-mode
versus vertex array mode.
So update the VBO code so that if the shader uses generic[0] but not gl_Vertex,
route the attribute data set with glVertex() to go to shader input generic[0].
No change needed for the glDrawArrays/Elements() path.
This is a potentially risky change so regressions are possible. All the usual
tests seem OK though.
(cherry picked from mesa, commit dea0d4d56326f148a42c766bdbaf1b5bb247cc59)
Follow-up: This patch doesn't seem to be as risky as noted above.
There have been no known regressions on Mesa/master because of it.
---
src/mesa/shader/slang/slang_link.c | 13 +++++++++++--
src/mesa/vbo/vbo_exec_api.c | 5 ++++-
src/mesa/vbo/vbo_exec_draw.c | 13 +++++++++++++
src/mesa/vbo/vbo_save_draw.c | 18 +++++++++++++++++-
4 files changed, 45 insertions(+), 4 deletions(-)
diff --git a/src/mesa/shader/slang/slang_link.c b/src/mesa/shader/slang/slang_link.c
index 4c1708e..b8427ca 100644
--- a/src/mesa/shader/slang/slang_link.c
+++ b/src/mesa/shader/slang/slang_link.c
@@ -318,7 +318,7 @@ _slang_resolve_attributes(struct gl_shader_program *shProg,
{
GLint attribMap[MAX_VERTEX_ATTRIBS];
GLuint i, j;
- GLbitfield usedAttributes;
+ GLbitfield usedAttributes; /* generics only, not legacy attributes */
assert(origProg != linkedProg);
assert(origProg->Target == GL_VERTEX_PROGRAM_ARB);
@@ -342,6 +342,15 @@ _slang_resolve_attributes(struct gl_shader_program *shProg,
usedAttributes |= (1 << attr);
}
+ /* If gl_Vertex is used, that actually counts against the limit
+ * on generic vertex attributes. This avoids the ambiguity of
+ * whether glVertexAttrib4fv(0, v) sets legacy attribute 0 (vert pos)
+ * or generic attribute[0]. If gl_Vertex is used, we want the former.
+ */
+ if (origProg->InputsRead & VERT_BIT_POS) {
+ usedAttributes |= 0x1;
+ }
+
/* initialize the generic attribute map entries to -1 */
for (i = 0; i < MAX_VERTEX_ATTRIBS; i++) {
attribMap[i] = -1;
@@ -384,7 +393,7 @@ _slang_resolve_attributes(struct gl_shader_program *shProg,
* Start at 1 since generic attribute 0 always aliases
* glVertex/position.
*/
- for (attr = 1; attr < MAX_VERTEX_ATTRIBS; attr++) {
+ for (attr = 0; attr < MAX_VERTEX_ATTRIBS; attr++) {
if (((1 << attr) & usedAttributes) == 0)
break;
}
diff --git a/src/mesa/vbo/vbo_exec_api.c b/src/mesa/vbo/vbo_exec_api.c
index d48f523..f6daa25 100644
--- a/src/mesa/vbo/vbo_exec_api.c
+++ b/src/mesa/vbo/vbo_exec_api.c
@@ -148,11 +148,14 @@ static void vbo_exec_copy_to_current( struct vbo_exec_context *exec )
/* Note: the exec->vtx.current[i] pointers point into the
* ctx->Current.Attrib and ctx->Light.Material.Attrib arrays.
*/
+ if (exec->vtx.attrptr[i]) {
+
COPY_CLEAN_4V(current,
exec->vtx.attrsz[i],
exec->vtx.attrptr[i]);
-
+ }
+
/* Given that we explicitly state size here, there is no need
* for the COPY_CLEAN above, could just copy 16 bytes and be
* done. The only problem is when Mesa accesses ctx->Current
diff --git a/src/mesa/vbo/vbo_exec_draw.c b/src/mesa/vbo/vbo_exec_draw.c
index 92356ba..ad8b6e8 100644
--- a/src/mesa/vbo/vbo_exec_draw.c
+++ b/src/mesa/vbo/vbo_exec_draw.c
@@ -175,7 +175,20 @@ static void vbo_exec_bind_arrays( GLcontext *ctx )
exec->vtx.inputs[attr + 16] = &vbo->generic_currval[attr];
}
map = vbo->map_vp_arb;
+
+ /* check if VERT_ATTRIB_POS is not read but VERT_BIT_GENERIC0 is read.
+ * In that case we effectively need to route the data from
+ * glVertexAttrib(0, val) calls to feed into the GENERIC0 input.
+ */
+ if ((ctx->VertexProgram._Current->Base.InputsRead & VERT_BIT_POS) == 0 &&
+ (ctx->VertexProgram._Current->Base.InputsRead & VERT_BIT_GENERIC0)) {
+ exec->vtx.inputs[16] = exec->vtx.inputs[0];
+ exec->vtx.attrsz[16] = exec->vtx.attrsz[0];
+ exec->vtx.attrsz[0] = 0;
+ }
break;
+ default:
+ assert(0);
}
/* Make all active attributes (including edgeflag) available as
diff --git a/src/mesa/vbo/vbo_save_draw.c b/src/mesa/vbo/vbo_save_draw.c
index ed82f09..ed40b5c 100644
--- a/src/mesa/vbo/vbo_save_draw.c
+++ b/src/mesa/vbo/vbo_save_draw.c
@@ -110,6 +110,9 @@ static void vbo_bind_vertex_list( GLcontext *ctx,
GLuint data = node->buffer_offset;
const GLuint *map;
GLuint attr;
+ GLubyte node_attrsz[VBO_ATTRIB_MAX]; /* copy of node->attrsz[] */
+
+ memcpy(node_attrsz, node->attrsz, sizeof(node->attrsz));
/* Install the default (ie Current) attributes first, then overlay
* all active ones.
@@ -135,13 +138,26 @@ static void vbo_bind_vertex_list( GLcontext *ctx,
save->inputs[attr + 16] = &vbo->generic_currval[attr];
}
map = vbo->map_vp_arb;
+
+ /* check if VERT_ATTRIB_POS is not read but VERT_BIT_GENERIC0 is read.
+ * In that case we effectively need to route the data from
+ * glVertexAttrib(0, val) calls to feed into the GENERIC0 input.
+ */
+ if ((ctx->VertexProgram._Current->Base.InputsRead & VERT_BIT_POS) == 0 &&
+ (ctx->VertexProgram._Current->Base.InputsRead & VERT_BIT_GENERIC0)) {
+ save->inputs[16] = save->inputs[0];
+ node_attrsz[16] = node_attrsz[0];
+ node_attrsz[0] = 0;
+ }
break;
+ default:
+ assert(0);
}
for (attr = 0; attr < VERT_ATTRIB_MAX; attr++) {
GLuint src = map[attr];
- if (node->attrsz[src]) {
+ if (node_attrsz[src]) {
/* override the default array set above */
save->inputs[attr] = &arrays[attr];
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