[英]Rotate camera around z axis by 45 degrees works but not around x axis
我正在嘗試在 C++ 中設置正交相機,但在正確獲得旋轉時遇到了一些問題。
當我嘗試將相機圍繞 z 軸旋轉 45 度時,一切都按預期工作(模型定義為 -0.5f 到 0.5f)。
然而,當試圖繞 x 軸旋轉時,角度確實被放大了(即繞 1 弧度旋轉使其幾乎消失)。
下面是相關代碼:
int main(int argc, char** argv)
{
sdl2::Context context;
sdl2::Window window("myWindow", 800, 600);
sdl2::GLContext glContext(window);
//make the shader
Shader shader("shaders/quad.vert", "shaders/quad.frag");
Quad quad;
//create a orthographic projection
glm::mat4 projection = glm::ortho(0.0f, 800.0f, 0.0f, 600.0f);
auto zAxis = glm::vec3(0.0f, 0.0f, 1.0f);
glUseProgram(shader.getID());
auto projectionLoc = glGetUniformLocation(shader.getID(), "projection");
glUniformMatrix4fv(projectionLoc, 1, false, glm::value_ptr(projection));
auto viewLoc = glGetUniformLocation(shader.getID(), "view");
auto viewTransform = glm::mat4(1.0f);
auto zRot = glm::quat(glm::vec3(glm::radians(1.0f), glm::radians(0.0f), glm::radians(0.0f)));
viewTransform *= glm::toMat4(zRot);
glUniformMatrix4fv(viewLoc, 1, true, glm::value_ptr(viewTransform));
bool quit = false;
SDL_Event e;
while (!quit)
{
while (SDL_PollEvent(&e) != 0)
{
if (e.type == SDL_QUIT)
{
quit = true;
}
}
glClear(GL_COLOR_BUFFER_BIT);
quad.render(shader);
SDL_GL_SwapWindow(window());
}
SDL_Delay(3000);
return 0;
}
#version 430 core
layout (location = 0) in vec3 pos;
layout (location = 1) in vec2 uv;
uniform mat4 projection;
uniform mat4 view;
uniform mat4 model;
void main()
{
gl_Position = projection * view * model * vec4(pos, 1.0);
}
Quad::Quad() :
_position(0, 0, 0)
{
glCreateBuffers(1, &_vbo);
glCreateVertexArrays(1, &_vao);
glGenBuffers(1, &_ebo);
float vertices[] = {
0.5f, 0.5f, 0.0f, // top right
0.5f, -0.5f, 0.0f, // bottom right
-0.5f, -0.5f, 0.0f, // bottom left
-0.5f, 0.5f, 0.0f // top left
};
uint32_t indices[] = {
0, 1, 3,
1, 2, 3
};
glBindVertexArray(_vao);
glBindBuffer(GL_ARRAY_BUFFER, _vbo);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, _ebo);
glEnableVertexAttribArray(0);
glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(indices), indices, GL_STATIC_DRAW);
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 3 * sizeof(float), (void*)0);
}
Quad::~Quad()
{
glDeleteVertexArrays(1, &_vao);
glDeleteBuffers(1, &_vbo);
}
void Quad::render(const Shader& shader)
{
glBindVertexArray(_vao);
glUseProgram(shader.getID());
auto modelView = glm::mat4(1.0f);
//modelView = glm::translate(modelView, glm::vec3(400.0f, 300.0f, 0.0f));
modelView = glm::scale(modelView, glm::vec3(400.0f, 400.0f, 1.0f));
//modelView = glm::scale(modelView, glm::vec3(800, 600, 0));
auto modelLoc = glGetUniformLocation(shader.getID(), "model");
auto viewLoc = glGetUniformLocation(shader.getID(), "view");
auto projectionLoc = glGetUniformLocation(shader.getID(), "projection");
glUniformMatrix4fv(modelLoc, 1, false, glm::value_ptr(modelView));
glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);
}
當您繞 x 或 y 軸旋轉時,對象將被Orthographic projection的近平面和遠平面裁剪。 默認情況下,近是 -1.0,遠是 1.0。 增加到近平面和遠平面的距離(參見glm::ortho
)。 例如:
glm::mat4 projection = glm::ortho(0.0f, 800.0f, 0.0f, 600.0f);
glm::mat4 projection = glm::ortho(0.0f, 800.0f, 0.0f, 600.0f, -500.0f, 500.0f);
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