github.com/cybriq/giocore@v0.0.7-0.20210703034601-cfb9cb5f3900/gpu/shaders/common.h (about)

     1  // SPDX-License-Identifier: Unlicense OR MIT
     2  
     3  struct m3x2 {
     4  	vec3 r0;
     5  	vec3 r1;
     6  };
     7  
     8  // fboTextureTransform is the transformation
     9  // that cancels the implied transformation between
    10  // the framebuffer and its texture.
    11  // Only two rows are returned. The last is implied
    12  // to be [0, 0, 1].
    13  const m3x2 fboTextureTransform = m3x2(
    14  #ifdef HLSL
    15  	vec3(1.0, 0.0, 0.0),
    16  	vec3(0.0, -1.0, 1.0)
    17  #else
    18  	vec3(1.0, 0.0, 0.0),
    19  	vec3(0.0, 1.0, 0.0)
    20  #endif
    21  );
    22  
    23  // fboTransform is the transformation
    24  // that cancels the implied transformation between
    25  // the clip space and the framebuffer.
    26  // Only two rows are returned. The last is implied
    27  // to be [0, 0, 1].
    28  const m3x2 fboTransform = m3x2(
    29  #ifdef HLSL
    30  	vec3(1.0, 0.0, 0.0),
    31  	vec3(0.0, 1.0, 0.0)
    32  #else
    33  	vec3(1.0, 0.0, 0.0),
    34  	vec3(0.0, -1.0, 0.0)
    35  #endif
    36  );
    37  
    38  // toClipSpace converts an OpenGL gl_Position value to a
    39  // native GPU position.
    40  vec4 toClipSpace(vec4 pos) {
    41  #ifdef HLSL
    42  	// Map depths to the Direct3D [0; 1] range.
    43  	return vec4(pos.xy, (pos.z + pos.w)*.5, pos.w);
    44  #else
    45  	return pos;
    46  #endif
    47  }
    48  
    49  vec3 transform3x2(m3x2 t, vec3 v) {
    50  	return vec3(dot(t.r0, v), dot(t.r1, v), dot(vec3(0.0, 0.0, 1.0), v));
    51  }