Fix T49861: Interlace stereo drawing

This does not address stapling shader in 2.8, though the solution can be
similar (own shader, not polutting interlace shader).

part of T49043

Reviewers: merwin

Differential Revision: https://developer.blender.org/D2440

7 files changed, 70 insertions, 160 deletions

diff --git a/source/blender/gpu/CMakeLists.txt b/source/blender/gpu/CMakeLists.txt
index 5643400ac66..c5531b8542e 100644
--- a/source/blender/gpu/CMakeLists.txt
+++ b/source/blender/gpu/CMakeLists.txt
@@ -142,6 +142,7 @@ data_to_c_simple(shaders/gpu_shader_image_modulate_alpha_frag.glsl SRC)
 data_to_c_simple(shaders/gpu_shader_image_color_frag.glsl SRC)
 data_to_c_simple(shaders/gpu_shader_image_rect_modulate_alpha_frag.glsl SRC)
 data_to_c_simple(shaders/gpu_shader_image_depth_linear_frag.glsl SRC)
+data_to_c_simple(shaders/gpu_shader_image_interlace_frag.glsl SRC)
 data_to_c_simple(shaders/gpu_shader_3D_image_vert.glsl SRC)
 data_to_c_simple(shaders/gpu_shader_3D_vert.glsl SRC)
 data_to_c_simple(shaders/gpu_shader_3D_flat_color_vert.glsl SRC)
diff --git a/source/blender/gpu/GPU_basic_shader.h b/source/blender/gpu/GPU_basic_shader.h
index d9bf3d1ced3..bfdf4ab6bbd 100644
--- a/source/blender/gpu/GPU_basic_shader.h
+++ b/source/blender/gpu/GPU_basic_shader.h
@@ -64,12 +64,6 @@ typedef enum GPUBasicShaderStipple {
 	GPU_SHADER_STIPPLE_HEXAGON                         = 3,
 	GPU_SHADER_STIPPLE_DIAG_STRIPES                    = 4,
 	GPU_SHADER_STIPPLE_DIAG_STRIPES_SWAP               = 5,
-	GPU_SHADER_STIPPLE_S3D_INTERLACE_ROW               = 6,
-	GPU_SHADER_STIPPLE_S3D_INTERLACE_ROW_SWAP          = 7,
-	GPU_SHADER_STIPPLE_S3D_INTERLACE_COLUMN            = 8,
-	GPU_SHADER_STIPPLE_S3D_INTERLACE_COLUMN_SWAP       = 9,
-	GPU_SHADER_STIPPLE_S3D_INTERLACE_CHECKER           = 10,
-	GPU_SHADER_STIPPLE_S3D_INTERLACE_CHECKER_SWAP      = 11
 } GPUBasicShaderStipple;
 
 void GPU_basic_shaders_init(void);
diff --git a/source/blender/gpu/GPU_shader.h b/source/blender/gpu/GPU_shader.h
index c6e4fb5e73a..394e751ed9b 100644
--- a/source/blender/gpu/GPU_shader.h
+++ b/source/blender/gpu/GPU_shader.h
@@ -112,6 +112,8 @@ typedef enum GPUBuiltinShader {
 	GPU_SHADER_3D_IMAGE_MODULATE_ALPHA,
 	GPU_SHADER_3D_IMAGE_RECT_MODULATE_ALPHA,
 	GPU_SHADER_3D_IMAGE_DEPTH,
+	/* stereo 3d */
+	GPU_SHADER_2D_IMAGE_INTERLACE,
 	/* points */
 	GPU_SHADER_2D_POINT_FIXED_SIZE_UNIFORM_COLOR,
 	GPU_SHADER_2D_POINT_UNIFORM_SIZE_UNIFORM_COLOR_SMOOTH,
@@ -128,6 +130,16 @@ typedef enum GPUBuiltinShader {
 	GPU_NUM_BUILTIN_SHADERS /* (not an actual shader) */
 } GPUBuiltinShader;
 
+/* Keep these in sync with:
+ *  gpu_shader_image_interlace_frag.glsl
+ *  gpu_shader_image_rect_interlace_frag.glsl
+ **/
+typedef enum GPUInterlaceShader {
+	GPU_SHADER_INTERLACE_ROW               = 0,
+	GPU_SHADER_INTERLACE_COLUMN            = 1,
+	GPU_SHADER_INTERLACE_CHECKER           = 2,
+} GPUInterlaceShader;
+
 GPUShader *GPU_shader_get_builtin_shader(GPUBuiltinShader shader);
 GPUShader *GPU_shader_get_builtin_fx_shader(int effects, bool persp);
 
diff --git a/source/blender/gpu/intern/gpu_basic_shader.c b/source/blender/gpu/intern/gpu_basic_shader.c
index 9d1e84cd44e..757982d1b30 100644
--- a/source/blender/gpu/intern/gpu_basic_shader.c
+++ b/source/blender/gpu/intern/gpu_basic_shader.c
@@ -140,114 +140,6 @@ const GLubyte stipple_checker_8px[128] = {
 	0, 255, 0, 255, 0, 255, 0, 255, 0, 255, 0, 255, 0, 255, 0, 255,
 	0, 255, 0, 255, 0, 255, 0, 255, 0, 255, 0, 255, 0, 255, 0, 255};
 
-const GLubyte stipple_interlace_row[128] = {
-	0xff, 0xff, 0xff, 0xff, 0x00, 0x00, 0x00, 0x00,
-	0xff, 0xff, 0xff, 0xff, 0x00, 0x00, 0x00, 0x00,
-	0xff, 0xff, 0xff, 0xff, 0x00, 0x00, 0x00, 0x00,
-	0xff, 0xff, 0xff, 0xff, 0x00, 0x00, 0x00, 0x00,
-	0xff, 0xff, 0xff, 0xff, 0x00, 0x00, 0x00, 0x00,
-	0xff, 0xff, 0xff, 0xff, 0x00, 0x00, 0x00, 0x00,
-	0xff, 0xff, 0xff, 0xff, 0x00, 0x00, 0x00, 0x00,
-	0xff, 0xff, 0xff, 0xff, 0x00, 0x00, 0x00, 0x00,
-	0xff, 0xff, 0xff, 0xff, 0x00, 0x00, 0x00, 0x00,
-	0xff, 0xff, 0xff, 0xff, 0x00, 0x00, 0x00, 0x00,
-	0xff, 0xff, 0xff, 0xff, 0x00, 0x00, 0x00, 0x00,
-	0xff, 0xff, 0xff, 0xff, 0x00, 0x00, 0x00, 0x00,
-	0xff, 0xff, 0xff, 0xff, 0x00, 0x00, 0x00, 0x00,
-	0xff, 0xff, 0xff, 0xff, 0x00, 0x00, 0x00, 0x00,
-	0xff, 0xff, 0xff, 0xff, 0x00, 0x00, 0x00, 0x00,
-	0xff, 0xff, 0xff, 0xff, 0x00, 0x00, 0x00, 0x00};
-
-const GLubyte stipple_interlace_row_swap[128] = {
-	0x00, 0x00, 0x00, 0x00, 0xff, 0xff, 0xff, 0xff,
-	0x00, 0x00, 0x00, 0x00, 0xff, 0xff, 0xff, 0xff,
-	0x00, 0x00, 0x00, 0x00, 0xff, 0xff, 0xff, 0xff,
-	0x00, 0x00, 0x00, 0x00, 0xff, 0xff, 0xff, 0xff,
-	0x00, 0x00, 0x00, 0x00, 0xff, 0xff, 0xff, 0xff,
-	0x00, 0x00, 0x00, 0x00, 0xff, 0xff, 0xff, 0xff,
-	0x00, 0x00, 0x00, 0x00, 0xff, 0xff, 0xff, 0xff,
-	0x00, 0x00, 0x00, 0x00, 0xff, 0xff, 0xff, 0xff,
-	0x00, 0x00, 0x00, 0x00, 0xff, 0xff, 0xff, 0xff,
-	0x00, 0x00, 0x00, 0x00, 0xff, 0xff, 0xff, 0xff,
-	0x00, 0x00, 0x00, 0x00, 0xff, 0xff, 0xff, 0xff,
-	0x00, 0x00, 0x00, 0x00, 0xff, 0xff, 0xff, 0xff,
-	0x00, 0x00, 0x00, 0x00, 0xff, 0xff, 0xff, 0xff,
-	0x00, 0x00, 0x00, 0x00, 0xff, 0xff, 0xff, 0xff,
-	0x00, 0x00, 0x00, 0x00, 0xff, 0xff, 0xff, 0xff,
-	0x00, 0x00, 0x00, 0x00, 0xff, 0xff, 0xff, 0xff};
-
-const GLubyte stipple_interlace_column[128] = {
-	0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55,
-	0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55,
-	0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55,
-	0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55,
-	0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55,
-	0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55,
-	0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55,
-	0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55,
-	0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55,
-	0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55,
-	0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55,
-	0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55,
-	0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55,
-	0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55,
-	0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55,
-	0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55, 0x55};
-
-const GLubyte stipple_interlace_column_swap[128] = {
-	0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa,
-	0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa,
-	0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa,
-	0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa,
-	0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa,
-	0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa,
-	0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa,
-	0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa,
-	0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa,
-	0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa,
-	0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa,
-	0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa,
-	0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa,
-	0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa,
-	0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa,
-	0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa, 0xaa};
-
-const GLubyte stipple_interlace_checker[128] = {
-	0x55, 0x55, 0x55, 0x55, 0xaa, 0xaa, 0xaa, 0xaa,
-	0x55, 0x55, 0x55, 0x55, 0xaa, 0xaa, 0xaa, 0xaa,
-	0x55, 0x55, 0x55, 0x55, 0xaa, 0xaa, 0xaa, 0xaa,
-	0x55, 0x55, 0x55, 0x55, 0xaa, 0xaa, 0xaa, 0xaa,
-	0x55, 0x55, 0x55, 0x55, 0xaa, 0xaa, 0xaa, 0xaa,
-	0x55, 0x55, 0x55, 0x55, 0xaa, 0xaa, 0xaa, 0xaa,
-	0x55, 0x55, 0x55, 0x55, 0xaa, 0xaa, 0xaa, 0xaa,
-	0x55, 0x55, 0x55, 0x55, 0xaa, 0xaa, 0xaa, 0xaa,
-	0x55, 0x55, 0x55, 0x55, 0xaa, 0xaa, 0xaa, 0xaa,
-	0x55, 0x55, 0x55, 0x55, 0xaa, 0xaa, 0xaa, 0xaa,
-	0x55, 0x55, 0x55, 0x55, 0xaa, 0xaa, 0xaa, 0xaa,
-	0x55, 0x55, 0x55, 0x55, 0xaa, 0xaa, 0xaa, 0xaa,
-	0x55, 0x55, 0x55, 0x55, 0xaa, 0xaa, 0xaa, 0xaa,
-	0x55, 0x55, 0x55, 0x55, 0xaa, 0xaa, 0xaa, 0xaa,
-	0x55, 0x55, 0x55, 0x55, 0xaa, 0xaa, 0xaa, 0xaa,
-	0x55, 0x55, 0x55, 0x55, 0xaa, 0xaa, 0xaa, 0xaa};
-
-const GLubyte stipple_interlace_checker_swap[128] = {
-	0xaa, 0xaa, 0xaa, 0xaa, 0x55, 0x55, 0x55, 0x55,
-	0xaa, 0xaa, 0xaa, 0xaa, 0x55, 0x55, 0x55, 0x55,
-	0xaa, 0xaa, 0xaa, 0xaa, 0x55, 0x55, 0x55, 0x55,
-	0xaa, 0xaa, 0xaa, 0xaa, 0x55, 0x55, 0x55, 0x55,
-	0xaa, 0xaa, 0xaa, 0xaa, 0x55, 0x55, 0x55, 0x55,
-	0xaa, 0xaa, 0xaa, 0xaa, 0x55, 0x55, 0x55, 0x55,
-	0xaa, 0xaa, 0xaa, 0xaa, 0x55, 0x55, 0x55, 0x55,
-	0xaa, 0xaa, 0xaa, 0xaa, 0x55, 0x55, 0x55, 0x55,
-	0xaa, 0xaa, 0xaa, 0xaa, 0x55, 0x55, 0x55, 0x55,
-	0xaa, 0xaa, 0xaa, 0xaa, 0x55, 0x55, 0x55, 0x55,
-	0xaa, 0xaa, 0xaa, 0xaa, 0x55, 0x55, 0x55, 0x55,
-	0xaa, 0xaa, 0xaa, 0xaa, 0x55, 0x55, 0x55, 0x55,
-	0xaa, 0xaa, 0xaa, 0xaa, 0x55, 0x55, 0x55, 0x55,
-	0xaa, 0xaa, 0xaa, 0xaa, 0x55, 0x55, 0x55, 0x55,
-	0xaa, 0xaa, 0xaa, 0xaa, 0x55, 0x55, 0x55, 0x55,
-	0xaa, 0xaa, 0xaa, 0xaa, 0x55, 0x55, 0x55, 0x55};
-
 const GLubyte stipple_hexagon[128] = {
 	0x88, 0x88, 0x88, 0x88, 0x88, 0x88, 0x88, 0x88,
 	0x22, 0x22, 0x22, 0x22, 0x22, 0x22, 0x22, 0x22,
@@ -651,24 +543,6 @@ void GPU_basic_shader_stipple(GPUBasicShaderStipple stipple_id)
 			case GPU_SHADER_STIPPLE_DIAG_STRIPES:
 				glPolygonStipple(stipple_diag_stripes_pos);
 				return;
-			case GPU_SHADER_STIPPLE_S3D_INTERLACE_ROW:
-				glPolygonStipple(stipple_interlace_row);
-				return;
-			case GPU_SHADER_STIPPLE_S3D_INTERLACE_ROW_SWAP:
-				glPolygonStipple(stipple_interlace_row_swap);
-				return;
-			case GPU_SHADER_STIPPLE_S3D_INTERLACE_COLUMN:
-				glPolygonStipple(stipple_interlace_column);
-				return;
-			case GPU_SHADER_STIPPLE_S3D_INTERLACE_COLUMN_SWAP:
-				glPolygonStipple(stipple_interlace_column_swap);
-				return;
-			case GPU_SHADER_STIPPLE_S3D_INTERLACE_CHECKER:
-				glPolygonStipple(stipple_interlace_checker);
-				return;
-			case GPU_SHADER_STIPPLE_S3D_INTERLACE_CHECKER_SWAP:
-				glPolygonStipple(stipple_interlace_checker_swap);
-				return;
 			default:
 				glPolygonStipple(stipple_hexagon);
 				return;
diff --git a/source/blender/gpu/intern/gpu_shader.c b/source/blender/gpu/intern/gpu_shader.c
index 5f41cda3fc2..b81c19d5c70 100644
--- a/source/blender/gpu/intern/gpu_shader.c
+++ b/source/blender/gpu/intern/gpu_shader.c
@@ -58,6 +58,7 @@ extern char datatoc_gpu_shader_2D_image_vert_glsl[];
 
 extern char datatoc_gpu_shader_3D_image_vert_glsl[];
 extern char datatoc_gpu_shader_image_color_frag_glsl[];
+extern char datatoc_gpu_shader_image_interlace_frag_glsl[];
 extern char datatoc_gpu_shader_image_mask_uniform_color_frag_glsl[];
 extern char datatoc_gpu_shader_image_modulate_alpha_frag_glsl[];
 extern char datatoc_gpu_shader_image_rect_modulate_alpha_frag_glsl[];
@@ -633,6 +634,9 @@ GPUShader *GPU_shader_get_builtin_shader(GPUBuiltinShader shader)
 		[GPU_SHADER_3D_IMAGE_DEPTH] = { datatoc_gpu_shader_3D_image_vert_glsl,
 		                                datatoc_gpu_shader_image_depth_linear_frag_glsl },
 
+	    [GPU_SHADER_2D_IMAGE_INTERLACE] = { datatoc_gpu_shader_2D_image_vert_glsl,
+	                                        datatoc_gpu_shader_image_interlace_frag_glsl },
+
 		[GPU_SHADER_2D_UNIFORM_COLOR] = { datatoc_gpu_shader_2D_vert_glsl, datatoc_gpu_shader_uniform_color_frag_glsl },
 		[GPU_SHADER_2D_FLAT_COLOR] = { datatoc_gpu_shader_2D_flat_color_vert_glsl,
 		                               datatoc_gpu_shader_flat_color_frag_glsl },
diff --git a/source/blender/gpu/shaders/gpu_shader_basic_frag.glsl b/source/blender/gpu/shaders/gpu_shader_basic_frag.glsl
index ed2339736e7..a0141f1ab2c 100644
--- a/source/blender/gpu/shaders/gpu_shader_basic_frag.glsl
+++ b/source/blender/gpu/shaders/gpu_shader_basic_frag.glsl
@@ -20,12 +20,6 @@
 #define STIPPLE_HEXAGON                                3
 #define STIPPLE_DIAG_STRIPES                           4
 #define STIPPLE_DIAG_STRIPES_SWAP                      5
-#define STIPPLE_S3D_INTERLACE_ROW                      6
-#define STIPPLE_S3D_INTERLACE_ROW_SWAP                 7
-#define STIPPLE_S3D_INTERLACE_COLUMN                   8
-#define STIPPLE_S3D_INTERLACE_COLUMN_SWAP              9
-#define STIPPLE_S3D_INTERLACE_CHECKERBOARD             10
-#define STIPPLE_S3D_INTERLACE_CHECKERBOARD_SWAP        11
 
 #if defined(USE_SOLID_LIGHTING) || defined(USE_SCENE_LIGHTING)
 #if defined(USE_FLAT_NORMAL)
@@ -74,14 +68,9 @@ void main()
 	/* We have to use mod function and integer casting.
 	 * This can be optimized further with the bitwise operations
 	 * when GLSL 1.3 is supported. */
-	if (stipple_id == STIPPLE_HALFTONE ||
-	    stipple_id == STIPPLE_S3D_INTERLACE_CHECKERBOARD ||
-	    stipple_id == STIPPLE_S3D_INTERLACE_CHECKERBOARD_SWAP)
-	{
+	if (stipple_id == STIPPLE_HALFTONE) {
 		int result = int(mod(gl_FragCoord.x + gl_FragCoord.y, 2));
 		bool dis = result == 0;
-		if (stipple_id == STIPPLE_S3D_INTERLACE_CHECKERBOARD_SWAP)
-			dis = !dis;
 		if (dis)
 			discard;
 	}
@@ -116,22 +105,6 @@ void main()
 		if (!((16 - modx > mody && mody > 8 - modx) || mody > 24 - modx))
 			discard;
 	}
-	else if (stipple_id == STIPPLE_S3D_INTERLACE_ROW || stipple_id == STIPPLE_S3D_INTERLACE_ROW_SWAP) {
-		int result = int(mod(gl_FragCoord.y, 2));
-		bool dis = result == 0;
-		if (stipple_id == STIPPLE_S3D_INTERLACE_ROW_SWAP)
-			dis = !dis;
-		if (dis)
-			discard;
-	}
-	else if (stipple_id == STIPPLE_S3D_INTERLACE_COLUMN || stipple_id == STIPPLE_S3D_INTERLACE_COLUMN_SWAP) {
-		int result = int(mod(gl_FragCoord.x, 2));
-		bool dis = result != 0;
-		if (stipple_id == STIPPLE_S3D_INTERLACE_COLUMN_SWAP)
-			dis = !dis;
-		if (dis)
-			discard;
-	}
 	else if (stipple_id == STIPPLE_HEXAGON) {
 		int mody = int(mod(gl_FragCoord.y, 2));
 		int modx = int(mod(gl_FragCoord.x, 4));
diff --git a/source/blender/gpu/shaders/gpu_shader_image_interlace_frag.glsl b/source/blender/gpu/shaders/gpu_shader_image_interlace_frag.glsl
new file mode 100644
index 00000000000..8b303104bb3
--- /dev/null
+++ b/source/blender/gpu/shaders/gpu_shader_image_interlace_frag.glsl
@@ -0,0 +1,52 @@
+
+/* Keep these in sync with GPU_shader.h */
+#define INTERLACE_ROW                      0
+#define INTERLACE_COLUMN                   1
+#define INTERLACE_CHECKERBOARD             2
+
+#if __VERSION__ == 120
+  varying vec2 texCoord_interp;
+  #define fragColor gl_FragColor
+#else
+  in vec2 texCoord_interp;
+  out vec4 fragColor;
+  #define texture2DRect texture
+#endif
+
+uniform int interlace_id;
+uniform sampler2DRect image_a;
+uniform sampler2DRect image_b;
+
+bool interlace()
+{
+#if __VERSION__ == 120
+	if (interlace_id == INTERLACE_CHECKERBOARD) {
+		return int(mod(gl_FragCoord.x + gl_FragCoord.y, 2)) != 0;
+	}
+	else if (interlace_id == INTERLACE_ROW) {
+		return int(mod(gl_FragCoord.y, 2)) != 0;
+	}
+	else if (interlace_id == INTERLACE_COLUMN) {
+		return int(mod(gl_FragCoord.x, 2)) != 0;
+	}
+#else
+	if (interlace_id == INTERLACE_CHECKERBOARD) {
+		return (int(gl_FragCoord.x + gl_FragCoord.y) & 1) != 0;
+	}
+	else if (interlace_id == INTERLACE_ROW) {
+		return (int(gl_FragCoord.y) & 1) != 0;
+	}
+	else if (interlace_id == INTERLACE_COLUMN) {
+		return (int(gl_FragCoord.x) & 1) != 0;
+	}
+#endif
+}
+
+void main()
+{
+	if (interlace()) {
+		fragColor = texture2DRect(image_a, texCoord_interp);
+	} else {
+		fragColor = texture2DRect(image_b, texCoord_interp);
+	}
+}