#version 450 core
+#extension GL_ARB_shader_viewport_layer_array : require
layout(location=0) in vec2 position;
-out vec2 tc, tc_left, tc_down;
+out vec3 tc, tc_left, tc_down;
+out vec3 equation_tc_assuming_left, equation_tc_assuming_right;
+out float element_x_idx;
out float element_sum_idx;
-uniform sampler2D diff_flow_tex, diffusivity_tex;
+uniform sampler2DArray diff_flow_tex, diffusivity_tex;
+uniform usampler2DArray equation_red_tex;
void main()
{
// 0.000 0.000 -2.000 -1.000
// 0.000 0.000 0.000 1.000
gl_Position = vec4(2.0 * position.x - 1.0, 2.0 * position.y - 1.0, -1.0, 1.0);
- tc = position;
- tc_left = vec2(tc.x - 0.5f / textureSize(diffusivity_tex, 0).x, tc.y);
- tc_down = vec2(tc.x, tc.y - 0.5f / textureSize(diffusivity_tex, 0).y);
+ gl_Layer = gl_InstanceID;
- vec2 element_idx = position * textureSize(diff_flow_tex, 0) - 0.5;
+ tc = vec3(position, gl_InstanceID);
+ tc_left = vec3(tc.x - 0.5f / textureSize(diffusivity_tex, 0).x, tc.y, gl_InstanceID);
+ tc_down = vec3(tc.x, tc.y - 0.5f / textureSize(diffusivity_tex, 0).y, gl_InstanceID);
+
+ // The equation textures have half the horizontal width, so we need to adjust the texel centers.
+ // It becomes extra tricky since the SOR texture might be of odd size, and then
+ // the equation texture is not exactly half the size.
+ vec2 element_idx = position * textureSize(diff_flow_tex, 0).xy - 0.5f;
+ float equation_texel_number_assuming_left = element_idx.x / 2.0f;
+ float equation_texel_number_assuming_right = (element_idx.x - 1.0f) / 2.0f;
+ equation_tc_assuming_left.x = (equation_texel_number_assuming_left + 0.5f) / textureSize(equation_red_tex, 0).x;
+ equation_tc_assuming_right.x = (equation_texel_number_assuming_right + 0.5f) / textureSize(equation_red_tex, 0).x;
+ equation_tc_assuming_left.y = tc.y;
+ equation_tc_assuming_right.y = tc.y;
+ equation_tc_assuming_left.z = gl_InstanceID;
+ equation_tc_assuming_right.z = gl_InstanceID;
+
+ element_x_idx = element_idx.x;
element_sum_idx = element_idx.x + element_idx.y;
}