#version 300 es
layout(location = 0) in vec3 Vertex_Position;
layout(location = 1) in vec3 Vertex_Normal;
layout(location = 2) in vec2 Vertex_Uv;
out vec2 v_Uv;
layout(std140) uniform CameraViewProj {
mat4 ViewProj;
};
layout(std140) uniform Transform { // set = 2, binding = 0
mat4 Model;
};
layout(std140) uniform Sprite { // set = 2, binding = 1
vec2 size;
uint flip;
};
void main() {
vec2 uv = Vertex_Uv;
// Flip the sprite if necessary by flipping the UVs
uint x_flip_bit = 1u; // The X flip bit
uint y_flip_bit = 2u; // The Y flip bit
// Note: Here we subtract f32::EPSILON from the flipped UV coord. This is due to reasons unknown
// to me (@zicklag ) that causes the uv's to be slightly offset and causes over/under running of
// the sprite UV sampling which is visible when resizing the screen.
float epsilon = 0.00000011920929;
if ((flip & x_flip_bit) == x_flip_bit) {
uv = vec2(1.0 - uv.x - epsilon, uv.y);
}
if ((flip & y_flip_bit) == y_flip_bit) {
uv = vec2(uv.x, 1.0 - uv.y - epsilon);
}
v_Uv = uv;
vec3 position = Vertex_Position * vec3(size, 1.0);
gl_Position = ViewProj * Model * vec4(position, 1.0);
}