Fix related to #30152, rainbow colours produced when loading hdr image to 3D viewport...
authorAntony Riakiotakis <kalast@gmail.com>
Tue, 14 Feb 2012 13:25:23 +0000 (13:25 +0000)
committerAntony Riakiotakis <kalast@gmail.com>
Tue, 14 Feb 2012 13:25:23 +0000 (13:25 +0000)
Issue is caused by scaling for power of 2 dimensions and mipmapping that happens through GLU. It looks like the library cannot handle float colour values above 1.0 correctly. Since we are close to release I will just clamp the srgb result for now even though it will result in a small performance loss for 16 bit textures only.

I tried a few things before that, glGenerateMipmaps + no scaling (supported for 2.0 GL hardware and up), or using our own scaling instead of glu among them which worked very nicely and gave a speedup too. However, since we are close to release and there may be issues with GPU mipmap generation, see:

http://www.gamedev.net/topic/495747-another-glgeneratemipmap-question/
(old discussion but better be sure than sorry)

I went for the most compatible solution. Maybe after release this can be tested if other devs agree.

source/blender/gpu/intern/gpu_draw.c
source/blender/imbuf/IMB_imbuf.h
source/blender/imbuf/intern/divers.c

index 1cd7974..7a61ee2 100644 (file)
@@ -518,6 +518,8 @@ int GPU_verify_image(Image *ima, ImageUser *iuser, int tftile, int compare, int
                                        IMB_buffer_float_from_float(srgb_frect, ibuf->rect_float,
                                                ibuf->channels, IB_PROFILE_SRGB, ibuf->profile, 0,
                                                ibuf->x, ibuf->y, ibuf->x, ibuf->x);
+                                       /* clamp buffer colours to 1.0 to avoid artifacts due to glu for hdr images */
+                                       IMB_buffer_float_clamp(srgb_frect, ibuf->x, ibuf->y);
                                        frect= srgb_frect + texwinsy*ibuf->x + texwinsx;
                                }
                                else
@@ -541,6 +543,8 @@ int GPU_verify_image(Image *ima, ImageUser *iuser, int tftile, int compare, int
                                        IMB_buffer_float_from_float(srgb_frect, ibuf->rect_float,
                                                        ibuf->channels, IB_PROFILE_SRGB, ibuf->profile, 0,
                                                        ibuf->x, ibuf->y, ibuf->x, ibuf->x);
+                                       /* clamp buffer colours to 1.0 to avoid artifacts due to glu for hdr images */
+                                       IMB_buffer_float_clamp(srgb_frect, ibuf->x, ibuf->y);
                                }
                                else
                                        frect= ibuf->rect_float;
@@ -615,7 +619,7 @@ int GPU_verify_image(Image *ima, ImageUser *iuser, int tftile, int compare, int
 
        if (!(gpu_get_mipmap() && mipmap)) {
                if(use_high_bit_depth)
-                       glTexImage2D(GL_TEXTURE_2D, 0,  GL_RGBA16,  rectw, recth, 0, GL_RGBA, GL_FLOAT, frect);                 
+                       glTexImage2D(GL_TEXTURE_2D, 0,  GL_RGBA16,  rectw, recth, 0, GL_RGBA, GL_FLOAT, frect);
                else
                        glTexImage2D(GL_TEXTURE_2D, 0,  GL_RGBA,  rectw, recth, 0, GL_RGBA, GL_UNSIGNED_BYTE, rect);
                glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
index 996bfd3..07f1b9e 100644 (file)
@@ -391,6 +391,7 @@ void IMB_buffer_float_from_float(float *rect_to, const float *rect_from,
 void IMB_buffer_byte_from_byte(unsigned char *rect_to, const unsigned char *rect_from,
        int profile_to, int profile_from, int predivide,
        int width, int height, int stride_to, int stride_from);
+void IMB_buffer_float_clamp(float *buf, int width, int height);
 
 /**
  * Change the ordering of the color bytes pointed to by rect from
index a8ca282..d9ec3bf 100644 (file)
@@ -742,3 +742,10 @@ void IMB_color_to_bw(ImBuf *ibuf)
                        rct[0]= rct[1]= rct[2]= rgb_to_grayscale_byte(rct);
        }
 }
+
+void IMB_buffer_float_clamp(float *buf, int width, int height){
+       int i, total = width*height*4;
+       for(i = 0; i < total; i++){
+               buf[i] = MIN2(1.0, buf[i]);
+       }
+}