mesa: increase number of texture units to MAX_COMBINED_TEXTURE_IMAGE_UNITS

We were misinterpretting GL_MAX_COMBINED_TEXTURE_IMAGE_UNITS previously.

It's the number of texture units for which we need to keep state; not
just the total number of texture units addressable by the vertex shader
plus fragment shader.

Since sw Mesa independently supports 16 texture units in vertex shaders
and 16 texture units in fragment shaders, the max combined units is 32.

Note that the docs for glActiveTexture() indicate the max legal unit is
MAX(GL_MAX_COMBINED_TEXTURE_IMAGE_UNITS, MAX_TEXTURE_COORDS) - 1.

A new piglit test (texunits.c) tests the various texture unit limits.

I'm pretty sure I've got this all right now, but additional reviews
are welcome...

1 files changed, 19 insertions, 10 deletions

diff --git a/src/mesa/main/texstate.c b/src/mesa/main/texstate.c
index 6f8831dfe0..8c4399a430 100644
--- a/src/mesa/main/texstate.c
+++ b/src/mesa/main/texstate.c
@@ -77,7 +77,7 @@ _mesa_copy_texture_state( const GLcontext *src, GLcontext *dst )
    dst->Texture.SharedPalette = src->Texture.SharedPalette;
 
    /* per-unit state */
-   for (u = 0; u < src->Const.MaxTextureImageUnits; u++) {
+   for (u = 0; u < src->Const.MaxCombinedTextureImageUnits; u++) {
       dst->Texture.Unit[u].Enabled = src->Texture.Unit[u].Enabled;
       dst->Texture.Unit[u].EnvMode = src->Texture.Unit[u].EnvMode;
       COPY_4V(dst->Texture.Unit[u].EnvColor, src->Texture.Unit[u].EnvColor);
@@ -282,15 +282,23 @@ calculate_derived_texenv( struct gl_tex_env_combine_state *state,
 void GLAPIENTRY
 _mesa_ActiveTextureARB(GLenum texture)
 {
-   GET_CURRENT_CONTEXT(ctx);
    const GLuint texUnit = texture - GL_TEXTURE0;
+   GLuint k;
+   GET_CURRENT_CONTEXT(ctx);
+
+   /* See OpenGL spec for glActiveTexture: */
+   k = MAX2(ctx->Const.MaxCombinedTextureImageUnits,
+            ctx->Const.MaxTextureCoordUnits);
+
+   ASSERT(k <= Elements(ctx->Texture.Unit));
+   
    ASSERT_OUTSIDE_BEGIN_END(ctx);
 
    if (MESA_VERBOSE & (VERBOSE_API|VERBOSE_TEXTURE))
       _mesa_debug(ctx, "glActiveTexture %s\n",
                   _mesa_lookup_enum_by_nr(texture));
 
-   if (texUnit >= ctx->Const.MaxTextureImageUnits) {
+   if (texUnit >= k) {
       _mesa_error(ctx, GL_INVALID_ENUM, "glActiveTexture(texture=%s)",
                   _mesa_lookup_enum_by_nr(texture));
       return;
@@ -510,7 +518,7 @@ update_texture_state( GLcontext *ctx )
    /*
     * Update texture unit state.
     */
-   for (unit = 0; unit < ctx->Const.MaxTextureImageUnits; unit++) {
+   for (unit = 0; unit < ctx->Const.MaxCombinedTextureImageUnits; unit++) {
       struct gl_texture_unit *texUnit = &ctx->Texture.Unit[unit];
       GLbitfield enabledVertTargets = 0x0;
       GLbitfield enabledFragTargets = 0x0;
@@ -760,14 +768,15 @@ _mesa_init_texture(GLcontext *ctx)
    ctx->Texture.SharedPalette = GL_FALSE;
    _mesa_init_colortable(&ctx->Texture.Palette);
 
-   for (u = 0; u < MAX_TEXTURE_UNITS; u++)
+   for (u = 0; u < Elements(ctx->Texture.Unit); u++)
       init_texture_unit(ctx, u);
 
    /* After we're done initializing the context's texture state the default
-    * texture objects' refcounts should be at least MAX_TEXTURE_UNITS + 1.
+    * texture objects' refcounts should be at least
+    * MAX_COMBINED_TEXTURE_IMAGE_UNITS + 1.
     */
    assert(ctx->Shared->DefaultTex[TEXTURE_1D_INDEX]->RefCount
-          >= MAX_TEXTURE_UNITS + 1);
+          >= MAX_COMBINED_TEXTURE_IMAGE_UNITS + 1);
 
    /* Allocate proxy textures */
    if (!alloc_proxy_textures( ctx ))
@@ -786,7 +795,7 @@ _mesa_free_texture_data(GLcontext *ctx)
    GLuint u, tgt;
 
    /* unreference current textures */
-   for (u = 0; u < MAX_TEXTURE_IMAGE_UNITS; u++) {
+   for (u = 0; u < Elements(ctx->Texture.Unit); u++) {
       /* The _Current texture could account for another reference */
       _mesa_reference_texobj(&ctx->Texture.Unit[u]._Current, NULL);
 
@@ -799,7 +808,7 @@ _mesa_free_texture_data(GLcontext *ctx)
    for (tgt = 0; tgt < NUM_TEXTURE_TARGETS; tgt++)
       ctx->Driver.DeleteTexture(ctx, ctx->Texture.ProxyTex[tgt]);
 
-   for (u = 0; u < MAX_TEXTURE_IMAGE_UNITS; u++)
+   for (u = 0; u < Elements(ctx->Texture.Unit); u++)
       _mesa_free_colortable_data(&ctx->Texture.Unit[u].ColorTable);
 }
 
@@ -814,7 +823,7 @@ _mesa_update_default_objects_texture(GLcontext *ctx)
 {
    GLuint u, tex;
 
-   for (u = 0; u < MAX_TEXTURE_UNITS; u++) {
+   for (u = 0; u < Elements(ctx->Texture.Unit); u++) {
       struct gl_texture_unit *texUnit = &ctx->Texture.Unit[u];
       for (tex = 0; tex < NUM_TEXTURE_TARGETS; tex++) {
          _mesa_reference_texobj(&texUnit->CurrentTex[tex],