From 8084b7e6e273e16a4441100a56570627128413da Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Cl=C3=A9ment=20Foucault?= <foucault.clem@gmail.com>
Date: Thu, 16 Jul 2020 02:50:55 +0200
Subject: Cleanup: GPU: Replace all glReadPixels by GPU equivalent

---
 source/blender/gpu/GPU_framebuffer.h        | 16 ++++--
 source/blender/gpu/intern/gpu_framebuffer.c | 79 ++++++++++++++++++++++-------
 2 files changed, 73 insertions(+), 22 deletions(-)

(limited to 'source/blender/gpu')

diff --git a/source/blender/gpu/GPU_framebuffer.h b/source/blender/gpu/GPU_framebuffer.h
index fcbe3ef2a78..6925839256b 100644
--- a/source/blender/gpu/GPU_framebuffer.h
+++ b/source/blender/gpu/GPU_framebuffer.h
@@ -28,7 +28,7 @@
 extern "C" {
 #endif
 
-struct GPUTexture;
+#include "GPU_texture.h"
 
 typedef struct GPUAttachment {
   struct GPUTexture *tex;
@@ -176,8 +176,15 @@ void GPU_framebuffer_clear(GPUFrameBuffer *fb,
 void GPU_framebuffer_multi_clear(GPUFrameBuffer *fb, const float (*clear_cols)[4]);
 
 void GPU_framebuffer_read_depth(GPUFrameBuffer *fb, int x, int y, int w, int h, float *data);
-void GPU_framebuffer_read_color(
-    GPUFrameBuffer *fb, int x, int y, int w, int h, int channels, int slot, float *data);
+void GPU_framebuffer_read_color(GPUFrameBuffer *fb,
+                                int x,
+                                int y,
+                                int w,
+                                int h,
+                                int channels,
+                                int slot,
+                                eGPUDataFormat format,
+                                void *data);
 
 void GPU_framebuffer_blit(GPUFrameBuffer *fb_read,
                           int read_slot,
@@ -214,6 +221,9 @@ void GPU_clear_color(float red, float green, float blue, float alpha);
 void GPU_clear_depth(float depth);
 void GPU_clear(eGPUFrameBufferBits flags);
 
+void GPU_frontbuffer_read_pixels(
+    int x, int y, int w, int h, int channels, eGPUDataFormat format, void *data);
+
 #ifdef __cplusplus
 }
 #endif
diff --git a/source/blender/gpu/intern/gpu_framebuffer.c b/source/blender/gpu/intern/gpu_framebuffer.c
index 3e806e1a982..366a1d17d69 100644
--- a/source/blender/gpu/intern/gpu_framebuffer.c
+++ b/source/blender/gpu/intern/gpu_framebuffer.c
@@ -640,31 +640,65 @@ void GPU_framebuffer_read_depth(GPUFrameBuffer *fb, int x, int y, int w, int h,
   glReadPixels(x, y, w, h, type, GL_FLOAT, data);
 }
 
-void GPU_framebuffer_read_color(
-    GPUFrameBuffer *fb, int x, int y, int w, int h, int channels, int slot, float *data)
+static GLenum gpu_get_gl_datatype(eGPUDataFormat format)
 {
-  CHECK_FRAMEBUFFER_IS_BOUND(fb);
+  switch (format) {
+    case GPU_DATA_FLOAT:
+      return GL_FLOAT;
+    case GPU_DATA_INT:
+      return GL_INT;
+    case GPU_DATA_UNSIGNED_INT:
+      return GL_UNSIGNED_INT;
+    case GPU_DATA_UNSIGNED_BYTE:
+      return GL_UNSIGNED_BYTE;
+    case GPU_DATA_UNSIGNED_INT_24_8:
+      return GL_UNSIGNED_INT_24_8;
+    case GPU_DATA_10_11_11_REV:
+      return GL_UNSIGNED_INT_10F_11F_11F_REV;
+    default:
+      BLI_assert(!"Unhandled data format");
+      return GL_FLOAT;
+  }
+}
 
-  GLenum type;
+static GLenum gpu_get_gl_channel_type(int channels)
+{
   switch (channels) {
     case 1:
-      type = GL_RED;
-      break;
+      return GL_RED;
     case 2:
-      type = GL_RG;
-      break;
+      return GL_RG;
     case 3:
-      type = GL_RGB;
-      break;
+      return GL_RGB;
     case 4:
-      type = GL_RGBA;
-      break;
+      return GL_RGBA;
     default:
-      BLI_assert(false && "wrong number of read channels");
-      return;
+      BLI_assert(!"Wrong number of read channels");
+      return GL_RED;
   }
-  glReadBuffer(GL_COLOR_ATTACHMENT0 + slot);
-  glReadPixels(x, y, w, h, type, GL_FLOAT, data);
+}
+
+static void gpu_framebuffer_read_color_ex(
+    int x, int y, int w, int h, int channels, GLenum readfb, eGPUDataFormat format, float *data)
+{
+  GLenum type = gpu_get_gl_channel_type(channels);
+  GLenum gl_format = gpu_get_gl_datatype(format);
+  glReadBuffer(readfb);
+  glReadPixels(x, y, w, h, type, gl_format, data);
+}
+
+void GPU_framebuffer_read_color(GPUFrameBuffer *fb,
+                                int x,
+                                int y,
+                                int w,
+                                int h,
+                                int channels,
+                                int slot,
+                                eGPUDataFormat format,
+                                void *data)
+{
+  CHECK_FRAMEBUFFER_IS_BOUND(fb);
+  gpu_framebuffer_read_color_ex(x, y, w, h, channels, GL_COLOR_ATTACHMENT0 + slot, format, data);
 }
 
 /* read_slot and write_slot are only used for color buffers. */
@@ -749,9 +783,9 @@ void GPU_framebuffer_blit(GPUFrameBuffer *fb_read,
 }
 
 /**
- * Use this if you need to custom down-sample your texture and use the previous mip level as input.
- * This function only takes care of the correct texture handling.
- * It execute the callback for each texture level.
+ * Use this if you need to custom down-sample your texture and use the previous mip level as
+ * input. This function only takes care of the correct texture handling. It execute the callback
+ * for each texture level.
  */
 void GPU_framebuffer_recursive_downsample(GPUFrameBuffer *fb,
                                           int max_lvl,
@@ -1035,3 +1069,10 @@ void GPU_clear(eGPUFrameBufferBits flags)
 {
   glClear(convert_buffer_bits_to_gl(flags));
 }
+
+void GPU_frontbuffer_read_pixels(
+    int x, int y, int w, int h, int channels, eGPUDataFormat format, void *data)
+{
+  glReadBuffer(GL_FRONT);
+  gpu_framebuffer_read_color_ex(x, y, w, h, channels, GL_FRONT, format, data);
+}
\ No newline at end of file
-- 
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