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Add function glm_perspective_lh_zo
This commit adds the function `glm_perspective_lh_zo`, modelled on the implementation of glm_perspective, but amended to provide a left-hand coordinate system expected by DirectX, Metal and Vulkan (per the GLM project's `glm/detail/setup.hpp`). It uses a clip-space of zero-to-one. The function is tested against a longhand version of the algorithm it seeks to implement as well as against the output of the GLM project's `glm::perspectiveLH_ZO` function. This commit adds a new subdirectory `test/glm_cmp` which contains a basic CMake file and `main.cpp`. An interested user should link or copy or clone the GLM project into this directory. The `main` function can be used to print the reference data used so others can verify behaviour in the future, or add new literal reference values.
This commit is contained in:
committed by
Tai Chi Minh Ralph Eastwood
parent
a242d83805
commit
1bce62c371
2
.gitignore
vendored
2
.gitignore
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@@ -76,3 +76,5 @@ build/
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conftest.dir/*
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conftest.dir/*
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confdefs.h
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confdefs.h
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*.xcuserdatad
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*.xcuserdatad
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.idea
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cmake-build-debug
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@@ -394,6 +394,10 @@ You can pass matrices the same way to other APIs e.g. Vulkan, DX...
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- This library uses float types only, does not support Integers, Double... yet
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- This library uses float types only, does not support Integers, Double... yet
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- If headers are not working properly with your compiler, IDE please open an issue, because I'm using GCC and clang to test it maybe sometimes MSVC
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- If headers are not working properly with your compiler, IDE please open an issue, because I'm using GCC and clang to test it maybe sometimes MSVC
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## Comparing cglm with glm results
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Contributors who wish to generate test results using the GLM library are pointed at the simple application in `test/glm_cmp`. A single file `test/glm_cmp/src/main.cpp` exists to which further functions can be added to print additional reference values. This is deliberately not part of the standard build.
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**TODO:**
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**TODO:**
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- [ ] Unit tests (In Progress)
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- [ ] Unit tests (In Progress)
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- [ ] Unit tests for comparing cglm with glm results
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- [ ] Unit tests for comparing cglm with glm results
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@@ -248,6 +248,39 @@ glm_perspective(float fovy, float aspect, float nearZ, float farZ, mat4 dest) {
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dest[3][2] = 2.0f * nearZ * farZ * fn;
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dest[3][2] = 2.0f * nearZ * farZ * fn;
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}
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}
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/*!
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* @brief set up perspective projection matrix with a left-hand coordinate
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* system (suitable for DirectX, Metal and Vulkan) and a clip-space with
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* depth values from zero to one.
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*
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* @param[in] fovy field of view angle
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* @param[in] aspect aspect ratio ( width / height )
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* @param[in] nearVal near clipping plane
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* @param[in] farVal far clipping planes
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* @param[out] dest result matrix
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*/
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CGLM_INLINE
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void
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glm_perspective_lh_zo(float fovy,
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float aspect,
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float nearVal,
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float farVal,
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mat4 dest) {
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/* Impl follows glm::perspectiveLH_ZO in glm/ext/matrix_clip_space.inl */
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float f, fn;
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glm_mat4_zero(dest);
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f = 1.0f / tanf(fovy * 0.5f);
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fn = 1.0f / (farVal - nearVal);
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dest[0][0] = f / aspect;
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dest[1][1] = f;
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dest[2][2] = farVal * fn;
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dest[2][3] = 1.0f;
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dest[3][2] = -(farVal * nearVal * fn);
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}
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/*!
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/*!
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* @brief extend perspective projection matrix's far distance
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* @brief extend perspective projection matrix's far distance
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*
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*
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1
test/glm_cmp/.gitignore
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1
test/glm_cmp/.gitignore
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glm
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12
test/glm_cmp/CMakeLists.txt
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12
test/glm_cmp/CMakeLists.txt
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cmake_minimum_required(VERSION 3.17)
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project(glm_cmp LANGUAGES CXX)
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set(CMAKE_CXX_STANDARD 14)
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set(CMP_MAIN glmcmp)
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add_subdirectory(glm)
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add_executable(${CMP_MAIN} src/main.cpp)
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target_link_libraries(${CMP_MAIN} PRIVATE glm)
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8
test/glm_cmp/README.md
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8
test/glm_cmp/README.md
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@@ -0,0 +1,8 @@
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### Simple GLM app for quick generation of reference values
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#### Usage
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1. Clone, link or copy the GLM library's root directory to `test/glm_cmp/glm`.
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1. Ensuring your current directory is `test/glm_cmp`:
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`mkdir build && cd build && cmake .. && make && ./glmcmp`
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Please do not delete prior reference-data-producing functions as it may be necessary to return to these to examine future bugs or assumptions. By all means remove or comment-out the call site from the `main` function, though, to focus on what you're working on.
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24
test/glm_cmp/src/main.cpp
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24
test/glm_cmp/src/main.cpp
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#include <stdio.h>
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#include "glm/glm.hpp"
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#include "glm/mat4x4.hpp"
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#include <glm/ext/matrix_clip_space.hpp>
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static void outputForPerspectiveLH_ZO() {
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const float fovy = glm::radians(45.0f);
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const float aspect = 640/480.0f;
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const float near = 0.1f;
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const float far = 100.0f;
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glm::mat4 cmp = glm::perspectiveLH_ZO(fovy, aspect, near, far);
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puts("mat4 cmp = {0};");
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printf("cmp[0][0] = %0.7ff;\n", cmp[0][0]);
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printf("cmp[1][1] = %0.7ff;\n", cmp[1][1]);
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printf("cmp[2][2] = %0.7ff;\n", cmp[2][2]);
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printf("cmp[2][3] = %0.7ff;\n", cmp[2][3]);
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printf("cmp[3][2] = %0.7ff;\n", cmp[3][2]);
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}
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int main(int argc, char** argv) {
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outputForPerspectiveLH_ZO();
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return 0;
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}
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@@ -7,6 +7,40 @@
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#include "test_common.h"
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#include "test_common.h"
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TEST_IMPL(perspective_lh_zo) {
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mat4 dst;
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const float fovy = glm_rad(45.0f);
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const float aspect = 640/480.0f;
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const float near = 0.1f;
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const float far = 100.0f;
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glm_perspective_lh_zo(fovy, aspect, near, far, dst);
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/* Sanity mk. I */
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/* Longhand version of what the above function _should_ be doing */
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ASSERT(test_eq(dst[0][0], 1 / (tanf(fovy / 2) * aspect)))
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ASSERT(test_eq(dst[1][1], 1 / tanf(fovy / 2)))
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ASSERT(test_eq(dst[2][2], far / (far - near)))
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ASSERT(test_eq(dst[2][3], 1.0f))
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ASSERT(test_eq(dst[3][2], -1 * far * near / (far - near)))
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/* Sanity mk. II */
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/* "Reference values" generated by GLM's glm::perspectiveLH_ZO */
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mat4 cmp = {0};
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cmp[0][0] = 1.8106601f;
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cmp[1][1] = 2.4142134f;
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cmp[2][2] = 1.0010010f;
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cmp[2][3] = 1.0000000f;
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cmp[3][2] = -0.1001001f;
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for (uint32_t i = 0 ; i < 16 ; i++) {
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uint32_t r = i%4, c = i/4;
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ASSERT(fabsf(dst[r][c] - cmp[r][c]) < GLM_FLT_EPSILON)
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}
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TEST_SUCCESS
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}
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TEST_IMPL(camera_lookat) {
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TEST_IMPL(camera_lookat) {
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mat4 view1, view2;
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mat4 view1, view2;
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vec3 center,
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vec3 center,
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@@ -223,6 +223,7 @@ TEST_DECLARE(glmc_mat2_swap_row)
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TEST_DECLARE(glmc_mat2_rmc)
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TEST_DECLARE(glmc_mat2_rmc)
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/* camera */
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/* camera */
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TEST_DECLARE(perspective_lh_zo)
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TEST_DECLARE(camera_lookat)
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TEST_DECLARE(camera_lookat)
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TEST_DECLARE(camera_decomp)
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TEST_DECLARE(camera_decomp)
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@@ -947,6 +948,7 @@ TEST_LIST {
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TEST_ENTRY(glmc_mat2_rmc)
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TEST_ENTRY(glmc_mat2_rmc)
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/* camera */
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/* camera */
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TEST_ENTRY(perspective_lh_zo)
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TEST_ENTRY(camera_lookat)
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TEST_ENTRY(camera_lookat)
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TEST_ENTRY(camera_decomp)
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TEST_ENTRY(camera_decomp)
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