尝试在不使用转换概念的情况下呈现此代码

Trying to render this code without using transformation concept

本文关键字：情况下 代码 转换      更新时间：2023-10-16

>我正在尝试在不使用变换函数的情况下更改三角形的位置， 通过每次只更改 x 的位置，

这是我在主 while 循环中的代码

float MyPoints[] = { 0.1 , 0.2, 0.3, 0.4, 0.5 , 0.6, 0.7, 0.8, 0.9};
int offset = (-1, 1);
for (int i = 0; i < sizeof(MyPoints); i++) {
offset += MyPoints[i];
ourShader.Use();
glBindVertexArray(VAO);
glDrawArrays(GL_TRIANGLES, 0, 3);
glBindVertexArray(0);// unbind
}

这是在着色器

out vec3 ourColor;
out vec2 TexCoord;
uniform vec4 offset;
void main() 
{
gl_Position = vec4(position.x + offset, position.y, position.z, 1.0f);
ourColor = color;
TexCoord = texCoord;
}

编辑

这是我在主 while 循环中的代码

float offset = 1.0f;
float step = 0.001f;  //move
int i=0;
// Loop until window closed (Game loop)
while (!glfwWindowShouldClose(mainWindow))
{
// Get + Handle user input events
glfwPollEvents();
//Render
// Clear the colorbuffer
glClearColor(0.0f, 0.1f, 0.2f, 1.0f);
//glPointSize(400.0f);
glClear(GL_COLOR_BUFFER_BIT);
// Call Shader Program
//Rendering the first triangle
GLuint program =ourShader.Program ; // program object from "ourShader"
GLint  offset_loc = glGetUniformLocation(program, "offset");
float MyPoints[] = { -0.1 , -0.2,-0.3,-0.4,-0.5 ,-0.6,-0.7,-0.8,-0.9 };
int noPoints = sizeof(MyPoints) / sizeof(float);
ourShader.Use();
for (int i = 0; i < noPoints; i++) {
glUniform1f(offset_loc, MyPoints[i] + offset);
}
offset += step;
if (MyPoints[i] + offset >= 1.0f || MyPoints[i] + offset <= -1.0f)
step *= -1.0f;
//update uniform data
glBindVertexArray(VAO);
glDrawArrays(GL_TRIANGLES, 0, 3);
glfwSwapBuffers(mainWindow);
glBindVertexArray(0);// unbind
}

这是在着色器

out vec3 ourColor;
out vec2 TexCoord;
uniform float offset;
void main() 
{
gl_Position = vec4(position.x + offset, position.y, position.z, 1.0f);
ourColor = color;
TexCoord = texCoord;
}

编辑代码从 (-1.0( 到窗口的中间到末尾

移动

首先数组中的元素数量是sizeof(MyPoints) / sizeof(float)。

必须float一致变量offset的类型：

uniform float offset;

您必须通过glGetUniformLocation获取均匀变量offset的位置，并通过例如glUniform1f：

GLuint program = ; // program object from "ourShader"
GLint  offset_loc = glGetUniformLocation(program, "offset");
float MyPoints[] = { 0.1 , 0.2, 0.3, 0.4, 0.5 , 0.6, 0.7, 0.8, 0.9};
int noPoints = sizeof(MyPoints) / sizeof(float);
// bind vertex array
glBindVertexArray(VAO);
// install program
ourShader.Use();
float offset = -1.0f;
for (int i = 0; i < noPoints; i++) {
// set value of the uniform (after program is installed)
offset += MyPoints[i];
glUniform1f(offset_loc, offset);
// draw one triangle
glDrawArrays(GL_TRIANGLES, 0, 3);
}
glBindVertexArray(0);

如果你想让三角形移动，那么你必须改变每一帧中每个三角形的偏移量。 例如：

float offset = 0.0f;
float step = 0.01f;
while (!glfwWindowShouldClose(mainWindow))
{
// [...]
ourShader.Use();
glUniform1f(offset_loc, offset);
glDrawArrays(GL_TRIANGLES, 0, 3);
// [...]
// change offset
offset += step;
if (offset >= 1.0f || offset <= -1.0f)
step *= -1.0f; // reverse direction
}
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