Fix #34909 Texture paint mode does not correctly update when using

textures larger than 2048x2048.

Check if texture is over user preference or GPU limit in texture paint
mode and if it is, scale the partial redraw rectangle before uploading
to GPU. This should be faster than rescaling the whole texture.

1 files changed, 89 insertions, 1 deletions

diff --git a/source/blender/gpu/intern/gpu_draw.c b/source/blender/gpu/intern/gpu_draw.c
index e98f8988aa6..fc28ec2d6f7 100644
--- a/source/blender/gpu/intern/gpu_draw.c
+++ b/source/blender/gpu/intern/gpu_draw.c
@@ -932,6 +932,77 @@ void GPU_paint_set_mipmap(int mipmap)
 	}
 }
 
+
+/* check if image has been downscaled and do scaled partial update */
+static bool GPU_check_scaled_image(ImBuf *ibuf, Image *ima, float *frect, int x, int y, int w, int h)
+{
+	if ((!GPU_non_power_of_two_support() && !is_power_of_2_resolution(ibuf->x, ibuf->y)) ||
+		is_over_resolution_limit(ibuf->x, ibuf->y))
+	{
+		int x_limit = smaller_power_of_2_limit(ibuf->x);
+		int y_limit = smaller_power_of_2_limit(ibuf->y);
+
+		float xratio = x_limit/(float)ibuf->x;
+		float yratio = y_limit/(float)ibuf->y;
+
+		/* find new width, height and x,y gpu texture coordinates */
+
+		/* take ceiling because we will be losing 1 pixel due to rounding errors in x,y... */
+		int rectw = (int)ceil(xratio * w);
+		int recth = (int)ceil(yratio * h);
+
+		x *= xratio;
+		y *= yratio;
+
+		/* ...but take back if we are over the limit! */
+		if (rectw + x > x_limit) rectw--;
+		if (recth + y > y_limit) recth--;
+
+		/* float rectangles are already continuous in memory so we can use gluScaleImage */
+		if (frect) {
+			float *fscalerect = MEM_mallocN(rectw*recth*sizeof(*fscalerect)*4, "fscalerect");
+			gluScaleImage(GL_RGBA, w, h, GL_FLOAT, frect, rectw, recth, GL_FLOAT, fscalerect);
+
+			glBindTexture(GL_TEXTURE_2D, ima->bindcode);
+			glTexSubImage2D(GL_TEXTURE_2D, 0, x, y, rectw, recth, GL_RGBA,
+					GL_FLOAT, fscalerect);
+
+			MEM_freeN(fscalerect);
+		}
+		/* byte images are not continuous in memory so do manual interpolation */
+		else {
+			unsigned char *scalerect= MEM_mallocN(rectw*recth*sizeof(*scalerect)*4, "scalerect");
+			unsigned int *p = (unsigned int *)scalerect;
+			int i, j;
+			float inv_xratio = 1.0/xratio;
+			float inv_yratio = 1.0/yratio;
+			for (i = 0; i < rectw; i++) {
+				float u = (x + i)*inv_xratio;
+				for (j = 0; j < recth; j++) {
+					float v = (y + j)*inv_yratio;
+					bilinear_interpolation_color_wrap(ibuf, (unsigned char *)(p + i + j * (rectw)), NULL, u, v);
+				}
+			}
+			glBindTexture(GL_TEXTURE_2D, ima->bindcode);
+			glTexSubImage2D(GL_TEXTURE_2D, 0, x, y, rectw, recth, GL_RGBA,
+					GL_UNSIGNED_BYTE, scalerect);
+
+			MEM_freeN(scalerect);
+		}
+
+		if (GPU_get_mipmap()) {
+			gpu_generate_mipmap(GL_TEXTURE_2D);
+		}
+		else {
+			ima->tpageflag &= ~IMA_MIPMAP_COMPLETE;
+		}
+
+		return true;
+	}
+
+	return false;
+}
+
 void GPU_paint_update_image(Image *ima, int x, int y, int w, int h)
 {
 	ImBuf *ibuf;
@@ -959,6 +1030,15 @@ void GPU_paint_update_image(Image *ima, int x, int y, int w, int h)
 			int is_data = (ima->tpageflag & IMA_GLBIND_IS_DATA);
 			IMB_partial_rect_from_float(ibuf, buffer, x, y, w, h, is_data);
 
+			if (GPU_check_scaled_image(ibuf, ima, buffer, x, y, w, h)) {
+				MEM_freeN(buffer);
+				glPixelStorei(GL_UNPACK_ROW_LENGTH, row_length);
+				glPixelStorei(GL_UNPACK_SKIP_PIXELS, skip_pixels);
+				glPixelStorei(GL_UNPACK_SKIP_ROWS, skip_rows);
+				BKE_image_release_ibuf(ima, ibuf, NULL);
+				return;
+			}
+
 			glBindTexture(GL_TEXTURE_2D, ima->bindcode);
 			glTexSubImage2D(GL_TEXTURE_2D, 0, x, y, w, h, GL_RGBA,
 					GL_FLOAT, buffer);
@@ -977,7 +1057,15 @@ void GPU_paint_update_image(Image *ima, int x, int y, int w, int h)
 			BKE_image_release_ibuf(ima, ibuf, NULL);
 			return;
 		}
-		
+
+		if (GPU_check_scaled_image(ibuf, ima, NULL, x, y, w, h)) {
+			glPixelStorei(GL_UNPACK_ROW_LENGTH, row_length);
+			glPixelStorei(GL_UNPACK_SKIP_PIXELS, skip_pixels);
+			glPixelStorei(GL_UNPACK_SKIP_ROWS, skip_rows);
+			BKE_image_release_ibuf(ima, ibuf, NULL);
+			return;
+		}
+
 		glBindTexture(GL_TEXTURE_2D, ima->bindcode);
 
 		glPixelStorei(GL_UNPACK_ROW_LENGTH, ibuf->x);