在将我的草图线绘制到屏幕上时，我遇到了 openGL 的问题，因为它似乎在原点添加了一个额外的点，而该点不在点列表中：
(0,0) 绝对不在要绘制的数组中的点中，只是似乎无法推理出来。我猜可能是我的数组大小太大或其他什么，但我看不到它
这是我用于填充数组和绘制调用的代码
void PointArray::repopulateObjectBuffer()
{
//Rebind Appropriate VAO
glBindVertexArray( vertex_array_object_id );
//Recalculate Array Size
vertexArraySize = points.size()*sizeof(glm::vec2);
//Rebind Appropriate VBO
glBindBuffer( GL_ARRAY_BUFFER, buffer_object_id );
glBufferData( GL_ARRAY_BUFFER, vertexArraySize, NULL, GL_STATIC_DRAW );
glBufferSubData( GL_ARRAY_BUFFER, 0, vertexArraySize, (const GLvoid*)(&points[0]) );
//Set up Vertex Arrays
glEnableVertexAttribArray( 0 ); //SimpleShader attrib at position 0 = "vPosition"
glVertexAttribPointer( (GLuint)0, 2, GL_FLOAT, GL_FALSE, 0, BUFFER_OFFSET(0) );
//Unbind
glBindBuffer(GL_ARRAY_BUFFER, 0);
glBindVertexArray(0);
}
void PointArray::draw() {
glBindVertexArray(vertex_array_object_id);
glLineWidth(4);
glDrawArrays( GL_LINE_STRIP, 0, vertexArraySize );
glBindVertexArray(0);
}
这是我在鼠标回调中添加点的地方
void mouseMovement(int x, int y)
{
mouseDX = x - lastX ;
mouseDY = y - lastY ;
lastX = x;
lastY = y;
if(mouse_drag)
{
cam->RotateByMouse(glm::vec2(mouseDX*mouseSens, mouseDY * mouseSens));
}
if(sketching)
{
sketchLine.addPoint(glm::vec2((float)x,(float)y));
sketchLine.repopulateObjectBuffer();
updatePickray(x,y);
}
}
最后是我简单的正交顶点着色器
in vec2 vPosition;
void main(){
const float right = 800.0;
const float bottom = 600.0;
const float left = 0.0;
const float top = 0.0;
const float far = 1.0;
const float near = -1.0;
mat4 orthoMat = mat4(
vec4(2.0 / (right - left), 0, 0, 0),
vec4(0, 2.0 / (top - bottom), 0, 0),
vec4(0, 0, -2.0 / (far - near), 0),
vec4(-(right + left) / (right - left), -(top + bottom) / (top - bottom), -(far + near) / (far - near), 1)
);
gl_Position = orthoMat * vec4(vPosition, 0.0, 1.0);
}