问题描述
当我想使用gluLookat并在其上放置着色器时,当我关闭着色器时,它不会移动相机".
When i want to use gluLookat and have the shaders on it doesnt move the "camera" when i turn the shaders off it works correctly.
我的着色器中是否缺少某些东西,我无法弄清楚是什么.
Is there something missing in my shaders, i cant figure out what.
void display(void)
{
glClear(GL_COLOR_BUFFER_BIT);
glClearColor(0.8, 0.8, 0.8, 0);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity();
gluLookAt(0.5,0,1,0.5,0,0,0,1,0);
glColor3f(0, 0, 0);
glDrawArrays(GL_TRIANGLES, 0, 6);
glDrawArrays(GL_LINES, 6, 6);
glDrawArrays(GL_TRIANGLES, 12,6);
glDrawArrays(GL_LINES, 18, 4);
glDrawArrays(GL_TRIANGLES, 22, 6);
glColor3f(1, 0.7, 0);
glDrawArrays(GL_TRIANGLES, 28, 6);
glFlush();
}
顶点着色器:
#version 450 core // 420, 330 core , compatibility
in vec4 position
out vec4 Color;
void main()
{
gl_Position = position;
}
片段着色器:
#version 450 core // 420, 330 core , compatibility
in vec4 Color;
layout(location=0) out vec4 fColor;
void main()
{
fColor = vec4(0,0,0,0);
}
将相机"移动到我希望着色器打开的位置
Move the "camera" to where i want it to be with shaders on
推荐答案
使用着色器程序时,当前矩阵不会神奇地处理顶点坐标属性.着色器程序必须执行顶点坐标的转换.
When you use a shader program, then the vertex coordinate attributes are not magically processed, by the current matrices. The shader program has to do the transformations of the vertex coordinates.
您有两种可能性,要么使用兼容性配置文件上下文,要么使用较低的glsl版本(例如1.10).
You've 2 possibilities, either you use a compatibility profile context and use a lower glsl version (e.g. 1.10).
然后,您可以使用内置的统一 gl_ModelViewProjectionMatrix
(请参见 GLSL 1.10加密)和固定功能矩阵堆栈将起作用:
Then you can use the built in uniform gl_ModelViewProjectionMatrix
(see GLSL 1.10 secification) and the fixed function matrix stack will work:
#version 110
attribute vec4 position
// varying vec4 Color;
void main()
{
// ...
gl_Position = gl_ModelViewProjectionMatrix * position;
}
但是请注意,此方法自几十年来就已被弃用.请参见固定功能管道和旧版OpenGL .
But note this is deprecated since decades. See Fixed Function Pipeline and Legacy OpenGL.
我建议使用 OpenGL数学之类的库进行计算 lookAt()
和统一变量:
I recommend to use a library like OpenGL Mathematics to calculate the view matrix by lookAt()
and a uniform variable:
#version 450 core // 420, 330 core , compatibility
in vec4 position
// out vec4 Color;
layout(location = 7) uniform mat4 view_matrix;
void main()
{
gl_Position = view_matrix * position;
}
#include <glm/glm.hpp>
#include <glm/gtc/matrix_transform.hpp>
#include <glm/gtc/type_ptr.hpp>
// [...]
{
// [...]
glUseProgram(program);
glm::mat4 view = glm::lookAt(
glm::vec3(0.5f,0.0f,1.0f), glm::Vec3(0.5f,0.0f,0.0f), glm::Vec3(0.0f,1.0f,0.0f));
glUniformMatrix4fv(7, 1, GL_FALSE, glm::value_ptr(view);
// [...]
}
统一位置由布局限定符明确设置. (location = 7
).
glUniformMatrix4fv
将制服的值设置为默认统一块中的指定位置.这必须在 glUseProgram
安装了密封胶之后进行.
The uniform location is set explicite by a Layout qualifier (location = 7
).glUniformMatrix4fv
sets the value of the uniform at the specified location in the default uniform block. This has to be done after the progroam was installed by glUseProgram
.
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