Workbench: StudioLight HDRI's

The Studio lights are now loaded from disk. The location is
`datafiles/studiolights` they need to be JPG for now. JPG cannot store
HDRI color range but they are clamped inside the Workbench
engine for speed reason. I didn't select JP2K as it might not be
enabled.

Users can add upto 20 HDRI files. This limitation is inside the
RNA_space.c Currently the icons are calculated when you first open the
selection box for the HDRI's. We could add them to a background
rendering later.

I added 2 test files a sky texture rendered in Cycles and an HDRI from
cloud.blender.org.

4 files changed, 17 insertions, 111 deletions

diff --git a/source/blender/draw/DRW_engine.h b/source/blender/draw/DRW_engine.h
index a1a2a36e75a..524a94e5886 100644
--- a/source/blender/draw/DRW_engine.h
+++ b/source/blender/draw/DRW_engine.h
@@ -135,5 +135,4 @@ void DRW_opengl_context_disable(void);
 
 void DRW_deferred_shader_remove(struct GPUMaterial *mat);
 
-uint *WORKBENCH_generate_studiolight_preview(int studiolight_id, int icon_size);
 #endif /* __DRW_ENGINE_H__ */
diff --git a/source/blender/draw/engines/workbench/workbench_materials.c b/source/blender/draw/engines/workbench/workbench_materials.c
index 0fee42619c3..680ac264233 100644
--- a/source/blender/draw/engines/workbench/workbench_materials.c
+++ b/source/blender/draw/engines/workbench/workbench_materials.c
@@ -338,6 +338,7 @@ void workbench_materials_cache_init(WORKBENCH_Data *vedata)
 	if (v3d) {
 		wpd->shading = v3d->shading;
 		wpd->drawtype = v3d->drawtype;
+		wpd->studio_light = BKE_studiolight_find(wpd->shading.studio_light);
 	}
 	else {
 		/* XXX: We should get the default shading from the view layer, after we implemented the render callback */
@@ -346,7 +347,9 @@ void workbench_materials_cache_init(WORKBENCH_Data *vedata)
 		wpd->shading.shadow_intensity = 0.5;
 		copy_v3_fl(wpd->shading.single_color, 0.8f);
 		wpd->drawtype = OB_SOLID;
+		wpd->studio_light = BKE_studiolight_findindex(0);
 	}
+	BKE_studiolight_ensure_flag(wpd->studio_light, STUDIOLIGHT_DIFFUSE_LIGHT_CALCULATED);
 
 	select_deferred_shaders(wpd);
 	/* Deferred Mix Pass */
@@ -360,7 +363,7 @@ void workbench_materials_cache_init(WORKBENCH_Data *vedata)
 		srgb_to_linearrgb_v3_v3(wd->background_color_high, wd->background_color_high);
 		srgb_to_linearrgb_v3_v3(wd->background_color_low, wd->background_color_low);
 
-		studiolight_update_world(wpd->shading.studio_light, wd);
+		studiolight_update_world(wpd->studio_light, wd);
 
 		wpd->world_ubo = DRW_uniformbuffer_create(sizeof(WORKBENCH_UBO_World), NULL);
 		DRW_uniformbuffer_update(wpd->world_ubo, &wpd->world_data);
diff --git a/source/blender/draw/engines/workbench/workbench_private.h b/source/blender/draw/engines/workbench/workbench_private.h
index 7a646d056b5..dde62302f62 100644
--- a/source/blender/draw/engines/workbench/workbench_private.h
+++ b/source/blender/draw/engines/workbench/workbench_private.h
@@ -27,6 +27,8 @@
 #define __WORKBENCH_PRIVATE_H__
 
 
+#include "BKE_studiolight.h"
+
 #include "DNA_image_types.h"
 #include "DNA_view3d_types.h"
 
@@ -81,6 +83,7 @@ typedef struct WORKBENCH_PrivateData {
 	struct GPUShader *prepass_texture_sh;
 	struct GPUShader *composite_sh;
 	View3DShading shading;
+	StudioLight *studio_light;
 	int drawtype;
 	struct GPUUniformBuffer *world_ubo;
 	struct DRWShadingGroup *shadow_shgrp;
@@ -127,6 +130,6 @@ void workbench_materials_solid_cache_populate(WORKBENCH_Data *vedata, Object *ob
 void workbench_materials_cache_finish(WORKBENCH_Data *vedata);
 
 /* workbench_studiolight.c */
-void studiolight_update_world(int studio_light, WORKBENCH_UBO_World *wd);
+void studiolight_update_world(StudioLight *sl, WORKBENCH_UBO_World *wd);
 
 #endif
diff --git a/source/blender/draw/engines/workbench/workbench_studiolight.c b/source/blender/draw/engines/workbench/workbench_studiolight.c
index 5b1d4432ca7..f7d107ea403 100644
--- a/source/blender/draw/engines/workbench/workbench_studiolight.c
+++ b/source/blender/draw/engines/workbench/workbench_studiolight.c
@@ -22,118 +22,19 @@
 /** \file workbench_studiolight.c
  *  \ingroup draw_engine
  */
+#include "BKE_studiolight.h"
+
 #include "DRW_engine.h"
 #include "workbench_private.h"
 
 #include "BLI_math.h"
 
-
-#define STUDIOLIGHT_X_POS 0
-#define STUDIOLIGHT_X_NEG 1
-#define STUDIOLIGHT_Y_POS 2
-#define STUDIOLIGHT_Y_NEG 3
-#define STUDIOLIGHT_Z_POS 4
-#define STUDIOLIGHT_Z_NEG 5
-
-const float studiolights[][6][3] = {
-	{
-		{1.0,  0.8,   0.6},
-		{1.0,  0.6,   0.6},
-		{0.9,  0.9,   1.0},
-		{0.05, 0.025, 0.025},
-		{0.8,  0.8,   0.75},
-		{1.0,  0.95,  0.8},
-	},
-	{
-		{0.0, 0.0, 0.0},
-		{0.0, 0.0, 0.0},
-		{0.0, 0.0, 0.0},
-		{0.0, 0.0, 0.0},
-		{0.8, 0.8, 1.0},
-		{0.0, 0.0, 0.0},
-	},
-	{
-		{0.4, 0.3, 0.8},
-		{0.4, 0.3, 0.8},
-		{0.8, 0.8, 0.2},
-		{0.0, 0.0, 0.0},
-		{0.4, 0.4, 0.8},
-		{0.0, 0.0, 0.0},
-	},
-	{
-		{0.2, 0.2, 0.0},
-		{0.8, 0.2, 0.0},
-		{0.8, 0.2, 0.0},
-		{0.2, 0.2, 0.0},
-		{0.8, 0.6, 0.4},
-		{0.0, 0.0, 0.0},
-	},
-	{
-		{0.8, 0.2, 0.0},
-		{0.8, 0.2, 0.0},
-		{0.8, 0.6, 0.0},
-		{0.2, 0.2, 0.0},
-		{1.0, 0.5, 0.0},
-		{0.0, 0.0, 0.0},
-	},
-};
-
-void studiolight_update_world(int studio_light, WORKBENCH_UBO_World *wd)
-{
-	copy_v3_v3(wd->diffuse_light_x_pos, studiolights[studio_light][STUDIOLIGHT_X_POS]);
-	copy_v3_v3(wd->diffuse_light_x_neg, studiolights[studio_light][STUDIOLIGHT_X_NEG]);
-	copy_v3_v3(wd->diffuse_light_y_pos, studiolights[studio_light][STUDIOLIGHT_Y_POS]);
-	copy_v3_v3(wd->diffuse_light_y_neg, studiolights[studio_light][STUDIOLIGHT_Y_NEG]);
-	copy_v3_v3(wd->diffuse_light_z_pos, studiolights[studio_light][STUDIOLIGHT_Z_POS]);
-	copy_v3_v3(wd->diffuse_light_z_neg, studiolights[studio_light][STUDIOLIGHT_Z_NEG]);
-}
-
-uint *WORKBENCH_generate_studiolight_preview(int studiolight_id, int icon_size)
+void studiolight_update_world(StudioLight *sl, WORKBENCH_UBO_World *wd)
 {
-	uint *rect = MEM_mallocN(icon_size * icon_size * sizeof(uint), __func__);
-	int icon_center = icon_size / 2;
-	float sphere_radius = icon_center * 0.9;
-
-	int offset = 0;
-	for (int y = 0; y < icon_size; y++) {
-		float dy = y - icon_center;
-		for (int x = 0; x < icon_size; x++) {
-			float dx = x - icon_center;
-			/* calculate aliasing */
-			float alias = 0;
-			const float alias_step = 0.2;
-			for (float ay = dy - 0.5; ay < dy + 0.5; ay += alias_step) {
-				for (float ax = dx - 0.5; ax < dx + 0.5; ax += alias_step) {
-					if (sqrt(ay * ay + ax * ax) < sphere_radius) {
-						alias += alias_step * alias_step;
-					}
-				}
-			}
-			uint pixelresult = 0x0;
-			uint alias_i = clamp_i(alias * 256, 0, 255);
-			if (alias_i != 0) {
-				/* calculate normal */
-				uint alias_mask = alias_i << 24;
-				float normal[3];
-				normal[0] = dx / sphere_radius;
-				normal[1] = dy / sphere_radius;
-				normal[2] = sqrt(-(normal[0] * normal[0]) - (normal[1] * normal[1]) + 1);
-				normalize_v3(normal);
-
-				float color[3];
-				mul_v3_v3fl(color, studiolights[studiolight_id][STUDIOLIGHT_X_POS], clamp_f(normal[0], 0.0, 1.0));
-				interp_v3_v3v3(color, color, studiolights[studiolight_id][STUDIOLIGHT_X_NEG], clamp_f(-normal[0], 0.0, 1.0));
-				interp_v3_v3v3(color, color, studiolights[studiolight_id][STUDIOLIGHT_Y_POS], clamp_f(normal[1], 0.0, 1.0));
-				interp_v3_v3v3(color, color, studiolights[studiolight_id][STUDIOLIGHT_Y_NEG], clamp_f(-normal[1], 0.0, 1.0));
-				interp_v3_v3v3(color, color, studiolights[studiolight_id][STUDIOLIGHT_Z_POS], clamp_f(normal[2], 0.0, 1.0));
-
-				pixelresult = rgb_to_cpack(
-				        linearrgb_to_srgb(color[0]),
-				        linearrgb_to_srgb(color[1]),
-				        linearrgb_to_srgb(color[2])) | alias_mask;
-			}
-			rect[offset++] = pixelresult;
-		}
-	}
-	return rect;
+	copy_v3_v3(wd->diffuse_light_x_pos, sl->diffuse_light[STUDIOLIGHT_X_POS]);
+	copy_v3_v3(wd->diffuse_light_x_neg, sl->diffuse_light[STUDIOLIGHT_X_NEG]);
+	copy_v3_v3(wd->diffuse_light_y_pos, sl->diffuse_light[STUDIOLIGHT_Y_POS]);
+	copy_v3_v3(wd->diffuse_light_y_neg, sl->diffuse_light[STUDIOLIGHT_Y_NEG]);
+	copy_v3_v3(wd->diffuse_light_z_pos, sl->diffuse_light[STUDIOLIGHT_Z_POS]);
+	copy_v3_v3(wd->diffuse_light_z_neg, sl->diffuse_light[STUDIOLIGHT_Z_NEG]);
 }