编辑:我正在考虑问题可能是在我加载顶点和索引时。也许关注那一节:)
我正在尝试从bmp文件加载高度图并在OpenGL中显示它。与我尝试的大多数事情一样,所有内容都编译并运行没有错误,但屏幕上没有任何内容。我似乎无法隔离这个问题,因为所有的代码都是独立工作的,但是当它们结合起来绘制地形时,没有任何作用。
地形类
我有一个地形类。它有2个VBO,1个IBO和1个VAO。它还存储顶点,索引,顶点颜色和高度。它是从bmp文件加载的。
加载地形:
Terrain* Terrain::loadTerrain(const std::string& filename, float height)
{
BitMap* bmp = BitMap::load(filename);
Terrain* t = new Terrain(bmp->width, bmp->length);
for(unsigned y = 0; y < bmp->length; y++)
{
for(unsigned x = 0; x < bmp->width; x++)
{
unsigned char color =
(unsigned char)bmp->pixels[3 * (y * bmp->width + x)];
float h = height * ((color / 255.0f) - 0.5f);
t->setHeight(x, y, h);
}
}
delete bmp;
t->initGL();
return t;
}
初始化缓冲区:
void Terrain::initGL()
{
// load vertices from heights data
vertices = new Vector4f[w * l];
int vertIndex = 0;
for(unsigned y = 0; y < l; y++)
{
for(unsigned x = 0; x < w; x++)
{
vertices[vertIndex++] = Vector4f((float)x, (float)y, heights[y][x], 1.0f);
}
}
// generate indices for indexed drawing
indices = new GLshort[(w - 1) * (l - 1) * 6]; // patch count * 6 (2 triangles per terrain patch)
int indicesIndex = 0;
for(unsigned y = 0; y < (l - 1); ++y)
{
for(unsigned x = 0; x < (w - 1); ++x)
{
int start = y * w + x;
indices[indicesIndex++] = (GLshort)start;
indices[indicesIndex++] = (GLshort)(start + 1);
indices[indicesIndex++] = (GLshort)(start + w);
indices[indicesIndex++] = (GLshort)(start + 1);
indices[indicesIndex++] = (GLshort)(start + 1 + w);
indices[indicesIndex++] = (GLshort)(start + w);
}
}
// generate colours for the vertices
colours = new Vector4f[w * l];
for(unsigned i = 0; i < w * l; i++)
{
colours[i] = Vector4f(0.0f, 1.0f, 0.0f, 1.0f); // let's make the entire terrain green
}
// THIS CODE WORKS FOR CUBES (BEGIN)
// vertex buffer object
glGenBuffers(1, &vbo);
glBindBuffer(GL_ARRAY_BUFFER, vbo);
glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
glBindBuffer(GL_ARRAY_BUFFER, 0);
// index buffer object
glGenBuffers(1, &ibo);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, ibo);
glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(indices), indices, GL_STATIC_DRAW);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, 0);
// colours vertex buffer object
glGenBuffers(1, &colour_vbo);
glBindBuffer(GL_ARRAY_BUFFER, colour_vbo);
glBufferData(GL_ARRAY_BUFFER, sizeof(colours), colours, GL_STATIC_DRAW);
glBindBuffer(GL_ARRAY_BUFFER, 0);
// create vertex array object
glGenVertexArrays(1, &vao);
glBindVertexArray(vao);
glBindBuffer(GL_ARRAY_BUFFER, vbo);
glEnableVertexAttribArray(0);
glVertexAttribPointer(0, 4, GL_FLOAT, GL_FALSE, 0, 0);
glBindBuffer(GL_ARRAY_BUFFER, colour_vbo);
glEnableVertexAttribArray(1);
glVertexAttribPointer(1, 4, GL_FLOAT, GL_FALSE, 0, 0);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, ibo);
glBindVertexArray(0);
// THIS CODE WORKS FOR CUBES (END)
}
我创建VBO,IBO和VAO的部分适用于立方体,它们绘制得很好。
渲染地形:
void Terrain::render()
{
glUseProgram(shaderProgram);
glBindVertexArray(vao);
int indices_length = (w - 1) * (l - 1) * 6;
glDrawElements(GL_TRIANGLES, indices_length, GL_UNSIGNED_SHORT, 0);
}
着色
这些是顶点和片段着色器。
顶点:
#version 330
layout (location = 0) in vec4 position;
layout (location = 1) in vec4 vertexColour;
out vec4 fragmentColour;
uniform vec3 offset;
uniform mat4 perspectiveMatrix;
void main()
{
vec4 cameraPos = position + vec4(offset.x, offset.y, offset.z, 0.0);
gl_Position = perspectiveMatrix * cameraPos;
fragmentColour = vertexColour;
}
片段:
#version 330
in vec4 fragmentColour;
out vec4 outputColour;
void main()
{
outputColour = fragmentColour;
}
透视矩阵
以下是“相机”的设置:
struct CameraSettings
{
static const float FRUSTUM_SCALE = 1.0f;
static const float Z_NEAR = 0.5f;
static const float Z_FAR = 3.0f;
static float perspective_matrix[16];
};
float CameraSettings::perspective_matrix[16] = {
FRUSTUM_SCALE,
0, 0, 0, 0,
FRUSTUM_SCALE,
0, 0, 0, 0,
(Z_FAR + Z_NEAR) / (Z_NEAR - Z_FAR),
-1.0f,
0, 0,
(2 * Z_FAR * Z_NEAR) / (Z_NEAR - Z_FAR),
0
};
在调用initGL()
后,制服会被填写:
// get offset uniform
offsetUniform = ShaderManager::getUniformLocation(shaderProgram, "offset");
perspectiveMatrixUniform = ShaderManager::getUniformLocation(shaderProgram, "perspectiveMatrix");
// set standard uniform data
glUseProgram(shaderProgram);
glUniform3f(offsetUniform, xOffset, yOffset, zOffset);
glUniformMatrix4fv(perspectiveMatrixUniform, 1, GL_FALSE, CameraSettings::perspective_matrix);
glUseProgram(0);
有人可以查看我的代码并提出建议吗?
答案 0 :(得分:4)
当你说:
时,我很确定 glBufferData(GL_ARRAY_BUFFER, sizeof(vertices), vertices, GL_STATIC_DRAW);
你其实想说:
glBufferData(GL_ARRAY_BUFFER, sizeof (Vector4f) * w * l, vertices, GL_STATIC_DRAW);
(与颜色缓冲区等相同)