[Bf-blender-cvs] [fa99d3e53b1] blender-v2.93-release: Fix T92807: Incorrect display planar tracking.

[Jeroen Bakker]

Commit: fa99d3e53b19df5c07999a90115bf52ac7886dc3
Author: Jeroen Bakker
Date:   Fri Nov 5 14:51:55 2021 +0100
Branches: blender-v2.93-release
https://developer.blender.org/rBfa99d3e53b19df5c07999a90115bf52ac7886dc3

Fix T92807: Incorrect display planar tracking.

Issue introduced in {7e66616b7e15} where the shader was replaced with a
2d image shader. This patch reverts several commits that removed the 3d
image shader.

===================================================================

M	source/blender/editors/space_clip/clip_draw.c
M	source/blender/gpu/CMakeLists.txt
M	source/blender/gpu/GPU_shader.h
M	source/blender/gpu/intern/gpu_shader_builtin.c
A	source/blender/gpu/shaders/gpu_shader_image_modulate_alpha_frag.glsl

===================================================================

diff --git a/source/blender/editors/space_clip/clip_draw.c b/source/blender/editors/space_clip/clip_draw.c
index 471b4a4bf5b..4bccb3664da 100644
--- a/source/blender/editors/space_clip/clip_draw.c
+++ b/source/blender/editors/space_clip/clip_draw.c
@@ -1219,10 +1219,11 @@ static void draw_plane_marker_image(Scene *scene,
       uint texCoord = GPU_vertformat_attr_add(
           imm_format, "texCoord", GPU_COMP_F32, 2, GPU_FETCH_FLOAT);
 
-      immBindBuiltinProgram(GPU_SHADER_2D_IMAGE_COLOR);
+      /* Use 3D image for correct display of planar tracked images. */
+      immBindBuiltinProgram(GPU_SHADER_3D_IMAGE_MODULATE_ALPHA);
 
       immBindTexture("image", texture);
-      immUniformColor4f(1.0f, 1.0f, 1.0f, plane_track->image_opacity);
+      immUniform1f("alpha", plane_track->image_opacity);
 
       immBegin(GPU_PRIM_TRI_FAN, 4);
 
diff --git a/source/blender/gpu/CMakeLists.txt b/source/blender/gpu/CMakeLists.txt
index 2ff72266a64..89b9d071bf7 100644
--- a/source/blender/gpu/CMakeLists.txt
+++ b/source/blender/gpu/CMakeLists.txt
@@ -219,6 +219,7 @@ data_to_c_simple(shaders/gpu_shader_image_frag.glsl SRC)
 data_to_c_simple(shaders/gpu_shader_image_desaturate_frag.glsl SRC)
 data_to_c_simple(shaders/gpu_shader_image_overlays_merge_frag.glsl SRC)
 data_to_c_simple(shaders/gpu_shader_image_overlays_stereo_merge_frag.glsl SRC)
+data_to_c_simple(shaders/gpu_shader_image_modulate_alpha_frag.glsl SRC)
 data_to_c_simple(shaders/gpu_shader_image_shuffle_color_frag.glsl SRC)
 data_to_c_simple(shaders/gpu_shader_image_color_frag.glsl SRC)
 data_to_c_simple(shaders/gpu_shader_image_varying_color_frag.glsl SRC)
diff --git a/source/blender/gpu/GPU_shader.h b/source/blender/gpu/GPU_shader.h
index 484ab95c980..cb61c6d89f1 100644
--- a/source/blender/gpu/GPU_shader.h
+++ b/source/blender/gpu/GPU_shader.h
@@ -249,6 +249,15 @@ typedef enum eGPUBuiltinShader {
   GPU_SHADER_2D_IMAGE_OVERLAYS_MERGE,
   GPU_SHADER_2D_IMAGE_OVERLAYS_STEREO_MERGE,
   GPU_SHADER_2D_IMAGE_SHUFFLE_COLOR,
+  /**
+   * Draw texture with alpha. Take a 3D position and a 2D texture coordinate for each vertex.
+   *
+   * \param alpha: uniform float
+   * \param image: uniform sampler2D
+   * \param texCoord: in vec2
+   * \param pos: in vec3
+   */
+  GPU_SHADER_3D_IMAGE_MODULATE_ALPHA,
   /* points */
   /**
    * Draw round points with a hardcoded size.
diff --git a/source/blender/gpu/intern/gpu_shader_builtin.c b/source/blender/gpu/intern/gpu_shader_builtin.c
index c5122b76001..d8fccabeea7 100644
--- a/source/blender/gpu/intern/gpu_shader_builtin.c
+++ b/source/blender/gpu/intern/gpu_shader_builtin.c
@@ -77,6 +77,7 @@ extern char datatoc_gpu_shader_image_overlays_merge_frag_glsl[];
 extern char datatoc_gpu_shader_image_overlays_stereo_merge_frag_glsl[];
 extern char datatoc_gpu_shader_image_color_frag_glsl[];
 extern char datatoc_gpu_shader_image_desaturate_frag_glsl[];
+extern char datatoc_gpu_shader_image_modulate_alpha_frag_glsl[];
 extern char datatoc_gpu_shader_image_varying_color_frag_glsl[];
 extern char datatoc_gpu_shader_image_shuffle_color_frag_glsl[];
 extern char datatoc_gpu_shader_3D_vert_glsl[];
@@ -178,7 +179,11 @@ static const GPUShaderStages builtin_shader_stages[GPU_SHADER_BUILTIN_LEN] = {
             .vert = datatoc_gpu_shader_3D_normal_vert_glsl,
             .frag = datatoc_gpu_shader_simple_lighting_frag_glsl,
         },
-
+    [GPU_SHADER_3D_IMAGE_MODULATE_ALPHA] =
+        {
+            .vert = datatoc_gpu_shader_3D_image_vert_glsl,
+            .frag = datatoc_gpu_shader_image_modulate_alpha_frag_glsl,
+        },
     [GPU_SHADER_2D_CHECKER] =
         {
             .name = "GPU_SHADER_2D_CHECKER",
diff --git a/source/blender/gpu/shaders/gpu_shader_image_modulate_alpha_frag.glsl b/source/blender/gpu/shaders/gpu_shader_image_modulate_alpha_frag.glsl
new file mode 100644
index 00000000000..613352b4ac8
--- /dev/null
+++ b/source/blender/gpu/shaders/gpu_shader_image_modulate_alpha_frag.glsl
@@ -0,0 +1,12 @@
+
+in vec2 texCoord_interp;
+out vec4 fragColor;
+
+uniform float alpha;
+uniform sampler2D image;
+
+void main()
+{
+  fragColor = texture(image, texCoord_interp);
+  fragColor.a *= alpha;
+}