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`.

4 files changed, 52 insertions, 39 deletions

diff --git a/source/blender/gpu/GPU_shader.h b/source/blender/gpu/GPU_shader.h
index baf3fb99974..40bae88f46d 100644
--- a/source/blender/gpu/GPU_shader.h
+++ b/source/blender/gpu/GPU_shader.h
@@ -94,13 +94,15 @@ void GPU_shader_set_srgb_uniform(const struct GPUShaderInterface *interface);
 int GPU_shader_get_uniform(GPUShader *shader, const char *name);
 int GPU_shader_get_builtin_uniform(GPUShader *shader, int builtin);
 int GPU_shader_get_uniform_block(GPUShader *shader, const char *name);
+
+int GPU_shader_get_uniform_block_binding(GPUShader *shader, const char *name);
+int GPU_shader_get_texture_binding(GPUShader *shader, const char *name);
+
 void GPU_shader_uniform_vector(
     GPUShader *shader, int location, int length, int arraysize, const float *value);
 void GPU_shader_uniform_vector_int(
     GPUShader *shader, int location, int length, int arraysize, const int *value);
 
-void GPU_shader_uniform_buffer(GPUShader *shader, int location, struct GPUUniformBuffer *ubo);
-void GPU_shader_uniform_texture(GPUShader *shader, int location, struct GPUTexture *tex);
 void GPU_shader_uniform_float(GPUShader *shader, int location, float value);
 void GPU_shader_uniform_int(GPUShader *shader, int location, int value);
 
diff --git a/source/blender/gpu/GPU_texture.h b/source/blender/gpu/GPU_texture.h
index a1e00793857..01814b78641 100644
--- a/source/blender/gpu/GPU_texture.h
+++ b/source/blender/gpu/GPU_texture.h
@@ -261,8 +261,9 @@ void GPU_texture_free(GPUTexture *tex);
 
 void GPU_texture_ref(GPUTexture *tex);
 void GPU_texture_bind(GPUTexture *tex, int number);
+void GPU_texture_bind_ex(GPUTexture *tex, int unit, const bool set_number);
 void GPU_texture_unbind(GPUTexture *tex);
-int GPU_texture_bound_number(GPUTexture *tex);
+void GPU_texture_unbind_all(void);
 
 void GPU_texture_copy(GPUTexture *dst, GPUTexture *src);
 
diff --git a/source/blender/gpu/intern/gpu_shader.c b/source/blender/gpu/intern/gpu_shader.c
index 97c2621de6b..66f98461047 100644
--- a/source/blender/gpu/intern/gpu_shader.c
+++ b/source/blender/gpu/intern/gpu_shader.c
@@ -746,6 +746,20 @@ int GPU_shader_get_uniform_block(GPUShader *shader, const char *name)
   return ubo ? ubo->location : -1;
 }
 
+int GPU_shader_get_uniform_block_binding(GPUShader *shader, const char *name)
+{
+  BLI_assert(shader && shader->program);
+  const GPUShaderInput *ubo = GPU_shaderinterface_ubo(shader->interface, name);
+  return ubo ? ubo->binding : -1;
+}
+
+int GPU_shader_get_texture_binding(GPUShader *shader, const char *name)
+{
+  BLI_assert(shader && shader->program);
+  const GPUShaderInput *tex = GPU_shaderinterface_uniform(shader->interface, name);
+  return tex ? tex->binding : -1;
+}
+
 void *GPU_shader_get_interface(GPUShader *shader)
 {
   return shader->interface;
@@ -833,34 +847,6 @@ void GPU_shader_uniform_int(GPUShader *UNUSED(shader), int location, int value)
   glUniform1i(location, value);
 }
 
-void GPU_shader_uniform_buffer(GPUShader *shader, int location, GPUUniformBuffer *ubo)
-{
-  int bindpoint = GPU_uniformbuffer_bindpoint(ubo);
-
-  if (location == -1) {
-    return;
-  }
-
-  glUniformBlockBinding(shader->program, location, bindpoint);
-}
-
-void GPU_shader_uniform_texture(GPUShader *UNUSED(shader), int location, GPUTexture *tex)
-{
-  int number = GPU_texture_bound_number(tex);
-
-  if (number == -1) {
-    fprintf(stderr, "Texture is not bound.\n");
-    BLI_assert(0);
-    return;
-  }
-
-  if (location == -1) {
-    return;
-  }
-
-  glUniform1i(location, number);
-}
-
 void GPU_shader_set_srgb_uniform(const GPUShaderInterface *interface)
 {
   const GPUShaderInput *srgb_uniform = GPU_shaderinterface_uniform_builtin(
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++) {