Fix T54329: brush texture preview not working.

With the removal of blender internal, the texture preview had to be
rewritten. Now we evaluate and write the texture directly to the
preview buffer instead of going through the renderer.

Differential Revision: https://developer.blender.org/D3670

1 files changed, 63 insertions, 1 deletions

diff --git a/source/blender/editors/render/render_preview.c b/source/blender/editors/render/render_preview.c
index 0059d782eaf..7253f07fea4 100644
--- a/source/blender/editors/render/render_preview.c
+++ b/source/blender/editors/render/render_preview.c
@@ -95,6 +95,7 @@
 
 #include "RE_pipeline.h"
 #include "RE_engine.h"
+#include "RE_shader_ext.h"
 
 #include "WM_api.h"
 #include "WM_types.h"
@@ -727,6 +728,61 @@ static void shader_preview_updatejob(void *spv)
 	}
 }
 
+/* Renders texture directly to render buffer. */
+static void shader_preview_texture(ShaderPreview *sp, Tex *tex, Scene* sce, Render *re)
+{
+	/* Setup output buffer. */
+	int width = sp->sizex;
+	int height = sp->sizey;
+
+	/* This is needed otherwise no RenderResult is created. */
+	sce->r.scemode &= ~R_BUTS_PREVIEW;
+	RE_InitState(re, NULL, &sce->r, &sce->view_layers, NULL, width, height, NULL);
+	RE_SetScene(re, sce);
+
+	/* Create buffer in empty RenderView created in the init step. */
+	RenderResult *rr = RE_AcquireResultWrite(re);
+	RenderView *rv = (RenderView *)rr->views.first;
+	rv->rectf = MEM_callocN(sizeof(float) * 4 * width * height, "texture render result");
+	RE_ReleaseResult(re);
+
+	/* Get texture image pool (if any) */
+	struct ImagePool *img_pool = BKE_image_pool_new();
+	BKE_texture_fetch_images_for_pool(tex, img_pool);
+
+	/* Fill in image buffer. */
+	float *rect_float = rv->rectf;
+	float tex_coord[3] = {0.0f, 0.0f, 0.0f};
+	bool color_manage = true;
+
+	for (int y = 0; y < height; y++) {
+		/* Tex coords between -1.0f and 1.0f. */
+		tex_coord[1] = ((float)y / (float)height) * 2.0f - 1.0f;
+
+		for (int x = 0; x < width; x++) {
+			tex_coord[0] = ((float)x / (float)height) * 2.0f - 1.0f;
+
+			/* Evaluate texture at tex_coord .*/
+			TexResult texres = {0};
+			BKE_texture_get_value_ex(sce, tex, tex_coord, &texres, img_pool, color_manage);
+
+			rect_float[0] = texres.tr;
+			rect_float[1] = texres.tg;
+			rect_float[2] = texres.tb;
+			rect_float[3] = 1.0f;
+
+			rect_float += 4;
+		}
+
+		/* Check if we should cancel texture preview. */
+		if (shader_preview_break(sp)) {
+			break;
+		}
+	}
+
+	BKE_image_pool_free(img_pool);
+}
+
 static void shader_preview_render(ShaderPreview *sp, ID *id, int split, int first)
 {
 	Render *re;
@@ -803,7 +859,13 @@ static void shader_preview_render(ShaderPreview *sp, ID *id, int split, int firs
 		((Camera *)sce->camera->data)->lens *= (float)sp->sizey / (float)sizex;
 
 	/* entire cycle for render engine */
-	RE_PreviewRender(re, pr_main, sce);
+	if (idtype == ID_TE) {
+		shader_preview_texture(sp, (Tex *)id, sce, re);
+	}
+	else {
+		/* Render preview scene */
+		RE_PreviewRender(re, pr_main, sce);
+	}
 
 	((Camera *)sce->camera->data)->lens = oldlens;