- float offset[2] = {
- left / output_width,
- (output_height - input_height - top) / output_height
- };
- set_uniform_vec2(glsl_program_num, prefix, "offset", offset);
-
- float scale[2] = {
- float(output_width) / input_width,
- float(output_height) / input_height
- };
- set_uniform_vec2(glsl_program_num, prefix, "scale", scale);
-
- // Due to roundoff errors, the test against 0.5 is seldom exact,
- // even though we test for less than and not less-than-or-equal.
- // We'd rather keep an extra border pixel in those very rare cases
- // (where the image is shifted pretty much exactly a half-pixel)
- // than losing a pixel in the common cases of integer shift.
- // Thus the 1e-3 fudge factors.
- float texcoord_min[2] = {
- float((0.5f - 1e-3) / input_width),
- float((0.5f - 1e-3) / input_height)
- };
- set_uniform_vec2(glsl_program_num, prefix, "texcoord_min", texcoord_min);
-
- float texcoord_max[2] = {
- float(1.0f - (0.5f - 1e-3) / input_width),
- float(1.0f - (0.5f - 1e-3) / input_height)
- };
- set_uniform_vec2(glsl_program_num, prefix, "texcoord_max", texcoord_max);
+ uniform_offset[0] = left / output_width;
+ uniform_offset[1] = (output_height - input_height - top) / output_height;
+
+ uniform_scale[0] = float(output_width) / input_width;
+ uniform_scale[1] = float(output_height) / input_height;
+
+ uniform_normalized_coords_to_texels[0] = float(input_width);
+ uniform_normalized_coords_to_texels[1] = float(input_height);
+
+ // Texels -0.5..0.5 should map to light level 0..1 (and then we
+ // clamp the rest).
+ uniform_offset_bottomleft[0] = 0.5f - border_offset_left;
+ uniform_offset_bottomleft[1] = 0.5f + border_offset_bottom;
+
+ // Texels size-0.5..size+0.5 should map to light level 1..0 (and then clamp).
+ uniform_offset_topright[0] = input_width + 0.5f + border_offset_right;
+ uniform_offset_topright[1] = input_height + 0.5f - border_offset_top;