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使用 glm::ortho(-width / 2, width / 2, -height/2, height, 0.1f, 10.0f) 时 glm::ortho() 拉伸；

[英]glm::ortho() streches when using glm::ortho(-width / 2, width / 2, -height/2, height, 0.1f, 10.0f);

 原文  2022-06-04 08:31:45  6   1    c++/ opengl/ projection/ glm-math/ orthographic

问题描述

I have been experimenting with 3d projection for a while,我一直在尝试 3d 投影，

but I've always used vertexes in -1 1 range I want to use units that are 1pixel big, so I use glm::ortho(-width / 2, width / 2, -height/2, height, 0.1f, 10.0f);但我一直使用 -1 1 范围内的顶点我想使用 1 像素大的单位，所以我使用 glm::ortho(-width / 2, width / 2, -height/2, height, 0.1f, 10.0 F）;

but that doesn't work但这不起作用

heres the code with glm::ortho(-1.0f, 1.0f, -1.0f, 1.0f, 0.1f,1.0f):下面是 glm::ortho(-1.0f, 1.0f, -1.0f, 1.0f, 0.1f,1.0f) 的代码：

#include "Engine.h"
#include "vendor/stb/stb_image.h"

float width = 1200;
float height = 750;

// edits in imgui files have farouk comment before them


int main(void)
{
    initGLFW();

GLFWimage icon;
icon.pixels = stbi_load("data/Images/Icon.png", &icon.width, &icon.height, nullptr, 4);

GLFWimage image;
image.pixels = stbi_load("data/Images/Cursor.png", &image.width, &image.height, nullptr, 4);
GLFWcursor * cursor = glfwCreateCursor(&image, image.width / 2, image.height / 2);

glfwWindowHint(GLFW_SAMPLES, 6);
glEnable(GL_MULTISAMPLE);

Window window("OGL", width, height, MVP());
Renderer renderer;

renderer.GenerateFonts({"data/fonts/arial.ttf", "data/fonts/Pixelboy.ttf"}, {"arial", "roboto"}, {64, 64});

// set perspective projection & set xyz ranges from -1, 1 to respective ranges
window.mvp.projection = glm::ortho(-1.0f, 1.0f, -1.0f, 1.0f, 0.1f, 10.0f);

window.createWindow("data/Images/Cursor.png", "data/Images/Icon.png");

glfwSetWindowIcon(window.window, 1, &icon);
glfwSetCursor(window.window, cursor);

stbi_image_free(image.pixels);
stbi_image_free(icon.pixels);

glfwMakeContextCurrent(window.window);
initGLEW(true);
glDepthMask(GL_TRUE);
glEnable(GL_DEPTH_TEST);
glDepthFunc(GL_LESS);

renderer.loadFonts({"arial", "roboto"});
initImGUI(window.window, "data/fonts/arial.ttf");

Shader shader("data/shaders/base.shader");


// TODO: Add Multiple Window Support (Window Manager)
// Addd .txt file for text with Characters map insteadt loaf Fonts
// texture in 3d space & 3d textures
// map -1, 1 to -width/2 , width/2


std::vector <Obj> cubes = {
{
        {
            { {-0.5, -0.5, -1.1}, {1,1,1,1} },
            { {-0.5, 0.5, -1.1}, {1,1,1,1} },
            { {0.5, 0.5, -1.1}, {1,1,1,1} },
            { {0.5, -0.5, -1.1}, {1,1,1,1} },

            { {-0.5, -0.5, -2.1}, {0,1,1,1} },
            { {-0.5, 0.5, -2.1}, {0,1,1,1} },
            { {0.5, 0.5, -2.1}, {0,1,1,1} },
            { {0.5, -0.5, -2.1}, {0,1,1,1} },

        },
        {
            0,1,2, 2,3,0, 4,5,6, 6,7,4, 0,4,5, 1,5,0
        },
        true
    }
};

float tx = 0;
float ty = 0;
float tz = 0;

while (!glfwWindowShouldClose(window.window) )
{
    glfwMakeContextCurrent(window.window);
    renderer.Clear({0.0, 0.0, 0.0, 1});


    // feed inputs to dear imgui, start new frame
    ImGui_ImplOpenGL3_NewFrame();
    ImGui_ImplGlfw_NewFrame();
    ImGui::NewFrame();

    renderer.Draw(shader, window.mvp, cubes);
    window.mvp.view = glm::translate(glm::mat4(1), glm::vec3(0, 0, -1.6)) * glm::rotate(glm::mat4(1), glm::radians(tx), glm::vec3(1,0,0)) * glm::rotate(glm::mat4(1), glm::radians(ty), glm::vec3(0,1,0)) * glm::rotate(glm::mat4(1), glm::radians(tz), glm::vec3(0,0,1));
    window.mvp.view = glm::translate(window.mvp.view, glm::vec3(0, 0, 1.6));
    renderer.Text(shader, MVP(glm::mat4(1.0), glm::mat4(1.0),glm::ortho(0.0, (double)width, 0.0, (double)height)), {(TextObj){"roboto", "FPS:" + std::to_string((int)ImGui::GetIO().Framerate), 0.01424501424f * height, 0.01424501424f * height, 0, 0.02849002849f * height, 0, {1,1,1,1}}});

    // render your GUI
    ImGui::Begin("Demo window");
    ImGui::Button("Hello!");
    ImGui::SliderFloat("x", &tx, 0, 360, "%.0f", 1.0f);
    ImGui::SliderFloat("y", &ty, 0, 360, "%.0f", 1.0f);
    ImGui::SliderFloat("z", &tz, 0, 360, "%.0f", 1.0f);
    ImGui::End();

    // Render dear imgui into screen
    ImGui::Render();
    ImGui_ImplOpenGL3_RenderDrawData(ImGui::GetDrawData());


    int display_w, display_h;
    glfwGetFramebufferSize(window.window, &display_w, &display_h);
    glViewport(0, 0, display_w, display_h);
    glfwSwapBuffers(window.window);
    glfwSwapInterval(1);
    glfwPollEvents();
}

ImGui_ImplOpenGL3_Shutdown();
ImGui_ImplGlfw_Shutdown();
ImGui::DestroyContext();

return 0;
}

and the output:和输出：

在此处输入图像描述

and heres the code with glm::ortho(-width / 2, width / 2, -height/2, height, 0.1f, 10.0f):下面是 glm::ortho(-width / 2, width / 2, -height/2, height, 0.1f, 10.0f) 的代码：

#include "Engine.h"
#include "vendor/stb/stb_image.h"

float width = 1200;
float height = 750;

// edits in imgui files have farouk comment before them


int main(void)
{
    initGLFW();
GLFWimage icon;
icon.pixels = stbi_load("data/Images/Icon.png", &icon.width, &icon.height, nullptr, 4);

GLFWimage image;
image.pixels = stbi_load("data/Images/Cursor.png", &image.width, &image.height, nullptr, 4);
GLFWcursor * cursor = glfwCreateCursor(&image, image.width / 2, image.height / 2);

glfwWindowHint(GLFW_SAMPLES, 6);
glEnable(GL_MULTISAMPLE);

Window window("OGL", width, height, MVP());
Renderer renderer;

renderer.GenerateFonts({"data/fonts/arial.ttf", "data/fonts/Pixelboy.ttf"}, {"arial", "roboto"}, {64, 64});

// set perspective projection & set xyz ranges from -1, 1 to respective ranges
window.mvp.projection = glm::ortho(-width / 2, width / 2, -height/2, height, 0.1f, 10.0f);

window.createWindow("data/Images/Cursor.png", "data/Images/Icon.png");

glfwSetWindowIcon(window.window, 1, &icon);
glfwSetCursor(window.window, cursor);

stbi_image_free(image.pixels);
stbi_image_free(icon.pixels);

glfwMakeContextCurrent(window.window);
initGLEW(true);
glDepthMask(GL_TRUE);
glEnable(GL_DEPTH_TEST);
glDepthFunc(GL_LESS);

renderer.loadFonts({"arial", "roboto"});
initImGUI(window.window, "data/fonts/arial.ttf");

Shader shader("data/shaders/base.shader");


// TODO: Add Multiple Window Support (Window Manager)
// Addd .txt file for text with Characters map insteadt loaf Fonts
// texture in 3d space & 3d textures
// map -1, 1 to -width/2 , width/2


std::vector <Obj> cubes = {
{
        {
            { {-300, -300, -1.1}, {1,1,1,1} },
            { {-300, 300, -1.1}, {1,1,1,1} },
            { {300, 300, -1.1}, {1,1,1,1} },
            { {300, -300, -1.1}, {1,1,1,1} },

            { {-300, -300, -2.1}, {0,1,1,1} },
            { {-300, 300, -2.1}, {0,1,1,1} },
            { {300, 300, -2.1}, {0,1,1,1} },
            { {300, -300, -2.1}, {0,1,1,1} },

        },
        {
            0,1,2, 2,3,0, 4,5,6, 6,7,4, 0,4,5, 1,5,0
        },
        true
    }
};

float tx = 0;
float ty = 0;
float tz = 0;

while (!glfwWindowShouldClose(window.window) )
{
    glfwMakeContextCurrent(window.window);
    renderer.Clear({0.0, 0.0, 0.0, 1});


    // feed inputs to dear imgui, start new frame
    ImGui_ImplOpenGL3_NewFrame();
    ImGui_ImplGlfw_NewFrame();
    ImGui::NewFrame();

    renderer.Draw(shader, window.mvp, cubes);
    window.mvp.view = glm::translate(glm::mat4(1), glm::vec3(0, 0, -1.6)) * glm::rotate(glm::mat4(1), glm::radians(tx), glm::vec3(1,0,0)) * glm::rotate(glm::mat4(1), glm::radians(ty), glm::vec3(0,1,0)) * glm::rotate(glm::mat4(1), glm::radians(tz), glm::vec3(0,0,1));
    window.mvp.view = glm::translate(window.mvp.view, glm::vec3(0, 0, 1.6));
    renderer.Text(shader, MVP(glm::mat4(1.0), glm::mat4(1.0),glm::ortho(0.0, (double)width, 0.0, (double)height)), {(TextObj){"roboto", "FPS:" + std::to_string((int)ImGui::GetIO().Framerate), 0.01424501424f * height, 0.01424501424f * height, 0, 0.02849002849f * height, 0, {1,1,1,1}}});

    // render your GUI
    ImGui::Begin("Demo window");
    ImGui::Button("Hello!");
    ImGui::SliderFloat("x", &tx, 0, 360, "%.0f", 1.0f);
    ImGui::SliderFloat("y", &ty, 0, 360, "%.0f", 1.0f);
    ImGui::SliderFloat("z", &tz, 0, 360, "%.0f", 1.0f);
    ImGui::End();

    // Render dear imgui into screen
    ImGui::Render();
    ImGui_ImplOpenGL3_RenderDrawData(ImGui::GetDrawData());


    int display_w, display_h;
    glfwGetFramebufferSize(window.window, &display_w, &display_h);
    glViewport(0, 0, display_w, display_h);
    glfwSwapBuffers(window.window);
    glfwSwapInterval(1);
    glfwPollEvents();
}

ImGui_ImplOpenGL3_Shutdown();
ImGui_ImplGlfw_Shutdown();
ImGui::DestroyContext();

return 0;
}

and the output:和输出： 在此处输入图像描述

notice that i chane the vertexes from 0.5 to 300 so thats not a problem请注意，我将顶点从 0.5 更改为 300，所以这不是问题

explanation of obj struct obj结构的解释

{ {

// vertexes -> vbo // 顶点 -> vbo

{ {-0.5, -0.5, -1.1}, {1,1,1,1} }, glm::vec3 pos, glm::vec4 col { {-0.5, -0.5, -1.1}, {1,1,1,1} }, glm::vec3 pos, glm::vec4 col

{ {-0.5, 0.5, -1.1}, {1,1,1,1} }, { {-0.5, 0.5, -1.1}, {1,1,1,1} },

{ {0.5, 0.5, -1.1}, {1,1,1,1} }, { {0.5, 0.5, -1.1}, {1,1,1,1} },

{ {0.5, -0.5, -1.1}, {1,1,1,1} }, { {0.5, -0.5, -1.1}, {1,1,1,1} },

{ {-0.5, -0.5, -2.1}, {0,1,1,1} }, { {-0.5, -0.5, -2.1}, {0,1,1,1} },

{ {-0.5, 0.5, -2.1}, {0,1,1,1} }, { {-0.5, 0.5, -2.1}, {0,1,1,1} },

{ {0.5, 0.5, -2.1}, {0,1,1,1} }, { {0.5, 0.5, -2.1}, {0,1,1,1} }，

{ {0.5, -0.5, -2.1}, {0,1,1,1} }, { {0.5, -0.5, -2.1}, {0,1,1,1} }，

}, },

{ // indexex -> ibo { // indexex -> ibo

0,1,2, 2,3,0, 4,5,6, 6,7,4, 0,4,5, 1,5,0 0,1,2, 2,3,0, 4,5,6, 6,7,4, 0,4,5, 1,5,0

}, },

true // fill -> GL_TRIANGLES or GL_LINES true // 填充 -> GL_TRIANGLES 或 GL_LINES

} }

1 个解决方案

解决方案1
 0  2022-06-04 12:20:53

Thanks to @derhass for the clarification the cuboid that I was drawing was too thin and my Z far value was too short I've adjusted it to 1000.0f and now everything works great感谢@derhass 的澄清，我绘制的长方体太薄，我的 Z 远值太短我已经将它调整为 1000.0f，现在一切正常

here is his comment:这是他的评论：

"The problem is that the cube becomes a line". “问题是立方体变成了一条线”。 There are no cubes in your vertex data, there is a cuboid sized 600x600x1, so if you look at it at certain angles, it will look very thin of course.你的顶点数据中没有立方体，有一个大小为 600x600x1 的长方体，所以如果你从某些角度看它，它当然会看起来很薄。 And furthermore, you will run into clipping issues as your z range is only 10 units.此外，由于 z 范围只有 10 个单位，您会遇到剪裁问题。

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