20 lines
869 B
Markdown
20 lines
869 B
Markdown
# Chapter 2: 3D Models
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As I read this book, I summarize what I think is wrong. If you think my comments are wrong then please let me know. We can dicuss more and update your opinion.
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## Metal coordinate system
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* The book doesn't mention that The Metal NDC(Normalized Device Coordinate) system is the left-hand coordinate system.
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* To show the train, this book modified the model file itself. It's not bad but I believe that the model file should be remained to original. Instead of changing y position to -1, we can modify the vertex shader code like below and get the same result.
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```
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vertex float4 vertex_main(const VertexIn vertex_in [[ stage_in ]]) {
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float4 position = vertex_in.position;
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position.y -= 1.0; // lower y position by -1
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return position;
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}
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```
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