(fix): fix GPU viewport and perspective matrix as opengl specific

VisualGMQ · May 29, 2023 · 04817dd · 04817dd
1 parent 976529b
commit 04817dd
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Showing 3 changed files with 6 additions and 2 deletions.
diff --git a/ReadMe.md b/ReadMe.md
@@ -54,3 +54,4 @@ cargo run --example sandbox --features gpu
 * [RenderHelp项目](https://github.com/skywind3000/RenderHelp)
 * [mini3d项目](https://github.com/skywind3000/mini3d)
 * [光栅化实现](https://www.scratchapixel.com/lessons/3d-basic-rendering/rasterization-practical-implementation/overview-rasterization-algorithm.html)
+* [图形学|shader|用一篇文章理解半透明渲染、透明度测试和混合、提前深度测试并彻底理清渲染顺序。](https://zhuanlan.zhihu.com/p/263566318)
diff --git a/src/camera.rs b/src/camera.rs
@@ -26,14 +26,16 @@ impl Frustum {
                     0.0,        0.0,         1.0, 0.0,
                     0.0,        0.0, -1.0 / near, 0.0,
                 ])
-            } else {
+            } else { // when in GPU, [we use opengl matrix](http://www.songho.ca/opengl/gl_projectionmatrix.html)
                 let half_w = near * fovy.tan();
                 let half_h = half_w / aspect;
+                let near = near.abs();
+                let far = far.abs();
                 // with far plane, clamp x,y,z in [-1, 1]
                 math::Mat4::from_row(&[
                     near / half_w,           0.0,                       0.0,                             0.0,
                               0.0, near / half_h,                       0.0,                             0.0,
-                              0.0,           0.0, far + near / (far - near), 2.0 * far * near / (far - near),
+                              0.0,           0.0, far + near / (near - far), 2.0 * far * near / (near - far),
                               0.0,           0.0,                      -1.0,                             0.0,
                 ])
             },

diff --git a/src/gpu_renderer.rs b/src/gpu_renderer.rs
@@ -97,6 +97,7 @@ impl RendererInterface for Renderer {
                 v.position.y = self.viewport.h as f32
                     - (v.position.y + 1.0) * 0.5 * (self.viewport.h as f32 - 1.0)
                     + self.viewport.y as f32;
+                v.position.w = (v.position.w + 1.0) / 2.0;
             }
 
             // find AABB for triangle