44 lines
1023 B
GLSL
44 lines
1023 B
GLSL
#type vertex
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#version 450 core
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layout(location = 0) in vec3 a_Position;
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out vec3 v_LocalPos;
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uniform mat4 u_Projection;
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uniform mat4 u_View;
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void main() {
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v_LocalPos = a_Position;
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// 只使用view的旋转部分，移除平移（与skybox一致）
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mat4 rotView = mat4(mat3(u_View));
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vec4 clipPos = u_Projection * rotView * vec4(a_Position, 1.0);
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gl_Position = clipPos.xyww; // 防止从立方体内部渲染时被近平面裁剪
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}
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#type fragment
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#version 450 core
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out vec4 FragColor;
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in vec3 v_LocalPos;
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uniform sampler2D u_EquirectangularMap;
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const vec2 invAtan = vec2(0.1591, 0.3183);
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vec2 SampleSphericalMap(vec3 v) {
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vec2 uv = vec2(atan(v.z, v.x), asin(v.y));
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uv *= invAtan;
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uv += 0.5;
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return uv;
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}
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void main() {
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vec2 uv = SampleSphericalMap(normalize(v_LocalPos));
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vec3 color = texture(u_EquirectangularMap, uv).rgb;
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// 限制极端HDR值，防止后续IBL生成时出现问题
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color = min(color, vec3(500.0));
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FragColor = vec4(color, 1.0);
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}
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