DRW: Remove automatic bind locations and use hardcoded locations for textures

This cleanup use the recent changes in shader interface to allow querying
the binding location a texture should use.

This should aleviate all issue we have with texture state change recompiling
the shaders at drawtime.

All binds are now treated like persistent binds and will stick until a new
shading group bind a different shader. The only difference is that you can
still change it with a new subgroup or same shader shgroup.

Since unbinding can be heavy we only do it when using `--debug-gpu`.

1 files changed, 32 insertions, 8 deletions

diff --git a/source/blender/gpu/intern/gpu_texture.c b/source/blender/gpu/intern/gpu_texture.c
index 69efd287218..95d33a03d93 100644
--- a/source/blender/gpu/intern/gpu_texture.c
+++ b/source/blender/gpu/intern/gpu_texture.c
@@ -1712,7 +1712,8 @@ void GPU_invalid_tex_free(void)
   }
 }
 
-void GPU_texture_bind(GPUTexture *tex, int unit)
+/* set_number is to save the the texture unit for setting texture parameters. */
+void GPU_texture_bind_ex(GPUTexture *tex, int unit, const bool set_number)
 {
   BLI_assert(unit >= 0);
 
@@ -1721,7 +1722,7 @@ void GPU_texture_bind(GPUTexture *tex, int unit)
     return;
   }
 
-  if ((G.debug & G_DEBUG)) {
+  if (G.debug & G_DEBUG) {
     for (int i = 0; i < GPU_TEX_MAX_FBO_ATTACHED; i++) {
       if (tex->fb[i] && GPU_framebuffer_bound(tex->fb[i])) {
         fprintf(stderr,
@@ -1733,7 +1734,10 @@ void GPU_texture_bind(GPUTexture *tex, int unit)
     }
   }
 
-  tex->number = unit;
+  if (set_number) {
+    tex->number = unit;
+  }
+
   glActiveTexture(GL_TEXTURE0 + unit);
 
   if (tex->bindcode != 0) {
@@ -1746,6 +1750,11 @@ void GPU_texture_bind(GPUTexture *tex, int unit)
   }
 }
 
+void GPU_texture_bind(GPUTexture *tex, int unit)
+{
+  GPU_texture_bind_ex(tex, unit, true);
+}
+
 void GPU_texture_unbind(GPUTexture *tex)
 {
   if (tex->number == -1) {
@@ -1758,10 +1767,25 @@ void GPU_texture_unbind(GPUTexture *tex)
   tex->number = -1;
 }
 
-int GPU_texture_bound_number(GPUTexture *tex)
+void GPU_texture_unbind_all(void)
 {
-  /* TODO remove. Makes no sense now. */
-  return tex->number;
+  /* Unbinding can be costly. Skip in normal condition. */
+  if (G.debug & G_DEBUG_GPU) {
+    for (int i = 0; i < GPU_max_textures(); i++) {
+      glActiveTexture(GL_TEXTURE0 + i);
+      glBindTexture(GL_TEXTURE_2D, 0);
+      glBindTexture(GL_TEXTURE_2D_ARRAY, 0);
+      glBindTexture(GL_TEXTURE_1D, 0);
+      glBindTexture(GL_TEXTURE_1D_ARRAY, 0);
+      glBindTexture(GL_TEXTURE_3D, 0);
+      glBindTexture(GL_TEXTURE_CUBE_MAP, 0);
+      glBindTexture(GL_TEXTURE_BUFFER, 0);
+      if (GPU_arb_texture_cube_map_array_is_supported()) {
+        glBindTexture(GL_TEXTURE_CUBE_MAP_ARRAY_ARB, 0);
+      }
+      glBindSampler(i, 0);
+    }
+  }
 }
 
 #define WARN_NOT_BOUND(_tex) \
@@ -1785,8 +1809,8 @@ void GPU_texture_generate_mipmap(GPUTexture *tex)
 
   if (GPU_texture_depth(tex)) {
     /* Some drivers have bugs when using glGenerateMipmap with depth textures (see T56789).
-     * In this case we just create a complete texture with mipmaps manually without down-sampling.
-     * You must initialize the texture levels using other methods like
+     * In this case we just create a complete texture with mipmaps manually without
+     * down-sampling. You must initialize the texture levels using other methods like
      * GPU_framebuffer_recursive_downsample(). */
     eGPUDataFormat data_format = gpu_get_data_format_from_tex_format(tex->format);
     for (int i = 1; i < levels; i++) {