我已经实现了一个简单的（慢速）方法，它可以模仿 OpenGL 即时模式来绘制线条。每一帧，我添加一对顶点，表示向量结构的线，以及添加一些指定或默认颜色到另一个向量结构。
void WindowsGraphicsManager::vertex(float x, float y, float z) {
vertices_.push_back(x);
vertices_.push_back(y);
vertices_.push_back(z);
colors_.push_back(vertexColor_.getR());
colors_.push_back(vertexColor_.getG());
colors_.push_back(vertexColor_.getB());
colors_.push_back(vertexColor_.getA());
}
在每一帧结束时，我清除这些向量。我的渲染代码如下所示：
void WindowsGraphicsManager::renderVertices(Mat4 mat) {
if (vertices_.size() == 0) {
return;
}
static Shader* shader = (Shader*) services_->getRM()->get(
Resource::SHADER, "openglimmediate");
glUseProgram(shader->getId());
shader->setMatrix4(Shader::WVP, mat);
glEnableVertexAttribArray(shader->getHandle(Shader::POS));
glVertexAttribPointer(shader->getHandle(Shader::POS),
3, GL_FLOAT, GL_FALSE, 0, &vertices_[0]);
glEnableVertexAttribArray(shader->getHandle(Shader::COL));
glVertexAttribPointer(shader->getHandle(Shader::COL),
4, GL_FLOAT, GL_FALSE, 0, &colors_[0]);
//LOGI("Before crash.");
//LOGI("Vertices size: %d", vertices_.size());
//LOGI("Colors size: %d", colors_.size());
//INFO: Vertices size: 607590
//INFO: Colors size: 810120
glDrawArrays(GL_LINES, 0, vertices_.size() / 3);
CHECK_GL_ERROR("Rendering lines.");
//LOGI("After crash.");
glDisableVertexAttribArray(shader->getHandle(Shader::COL));
glDisableVertexAttribArray(shader->getHandle(Shader::POS));
vertices_.clear();
colors_.clear();
}
当我将 607590 个浮点数（顶点除以 3）添加到顶点向量时，使用 glDrawArrays 函数在线渲染崩溃。奇怪的是，当我第一次最大化窗口并渲染时，它适用于具有 607590 个浮点数的模型，尽管对于具有 ~800k 个浮点数的模型它仍然崩溃。
这可能是什么原因造成的？
[编辑] 在渲染顶点之前，我调用了另一种方法。删除它后，渲染停止崩溃，所以我想我在这里做错了。
inline void WindowsGraphicsManager::renderNode(
Node* node, Mat4 mat, bool ortho)
{
if (!node->getState(Node::RENDERABLE)) {
return;
}
// Retrieve model data.
Renderable* renderable = 0;
Resource* resource = 0;
if (node->hasResource(Resource::SPRITE)) {
resource = node->getResource(Resource::SPRITE);
renderable = dynamic_cast<Renderable*>(resource);
}
else if (node->hasResource(Resource::STATIC_OBJECT)) {
resource = node->getResource(Resource::STATIC_OBJECT);
renderable = dynamic_cast<Renderable*>(resource);
StaticObject* so = static_cast<StaticObject*>(resource);
// Check for frustum culling.
if (so->getBoundingVolume() != 0
&& so->getBoundingVolume()->isInFrustum(
services_->getCamera(), node->getPos())
== BoundingVolume::OUTSIDE)
{
return;
}
}
else if (node->hasResource(Resource::DYNAMIC_OBJECT)) {
resource = node->getResource(Resource::DYNAMIC_OBJECT);
renderable = dynamic_cast<Renderable*>(resource);
}
if (renderable == 0) {
LOGW("Renderable with name \"%s\" is null.",
node->getName().c_str());
return;
}
// Retrieve node shader or use default.
Shader* shader = static_cast<Shader*>(
node->getResource(Resource::SHADER));
if (shader == 0) {
LOGW("Unable to retrieve shader for node: %s.",
node->getName().c_str());
return;
}
int shaderId = shader->getId();
// Select shader program to use.
glUseProgram(shaderId);
CHECK_GL_ERROR("glUseProgram");
Mat4 res;
if (!ortho) {
Matrix::multiply(mat, node->getMatrix(), res);
}
else {
Mat4 tmp;
Mat4 pos;
Mat4 rot;
Mat4 scale;
Vec3 p = node->getPos();
Vec3 r = node->getRot();
Vec3 s = node->getScale();
float width = s.getX();
float height = s.getY();
float x = p.getX();
float y = p.getY();
Matrix::translate(pos, x, y, p.getZ());
Matrix::rotateXYZ(rot, r.getX(), r.getY(), r.getZ());
Matrix::scale(scale, width, height, 1.0f);
Matrix::multiply(mat, pos, res);
Matrix::multiply(res, rot, tmp);
Matrix::multiply(tmp, scale, res);
}
// World * View * Projection matrix.
shader->setMatrix4(Shader::WVP, res);
// World matrix.
shader->setMatrix4(Shader::W, node->getMatrix());
// Normal matrix.
if (shader->hasHandle(Shader::N)) {
Mat3 normalMatrix;
Matrix::toMat3(node->getMatrix(), normalMatrix);
shader->setMatrix3(Shader::N, normalMatrix);
}
// Light position.
float* lightPos = new float[lights_.size() * 3];
if (lights_.size() > 0 && shader->hasHandle(Shader::LIGHT_POS)) {
for (UINT i = 0; i < lights_.size(); i++) {
Vec3& pos = lights_[i]->getPos();
lightPos[i * 3 + 0] = pos.getX();
lightPos[i * 3 + 1] = pos.getY();
lightPos[i * 3 + 2] = pos.getZ();
}
shader->setVector3(Shader::LIGHT_POS, lightPos, lights_.size());
}
delete lightPos;
// Light count.
shader->setInt(Shader::LIGHT_COUNT, lights_.size());
//shader->setVector3(Shader::LIGHT_POS,
// services_->getEnv()->getSunPos()->toArray());
// Eye position.
shader->setVector3(Shader::EYE_POS,
services_->getCamera()->getPos().toArray());
// Fog color.
if (shader->hasHandle(Shader::FOG_COLOR)) {
shader->setVector3(Shader::FOG_COLOR,
services_->getEnv()->getFogColor());
}
// Fog density.
shader->setFloat(Shader::FOG_DENSITY, services_->getEnv()->getFogDensity());
// Timer.
shader->setFloat(Shader::TIMER,
(float) services_->getSystem()->getTimeElapsed());
// Bind combined buffer object.
if (renderable->getCBO() > 0) {
int stride = renderable->getVertexStride();
glBindBuffer(GL_ARRAY_BUFFER, renderable->getCBO());
if (shader->hasHandle(Shader::POS)) {
glEnableVertexAttribArray(shader->getHandle(Shader::POS));
glVertexAttribPointer(
shader->getHandle(Shader::POS), 3, GL_FLOAT, GL_FALSE,
stride, ((char*) 0) + renderable->getPosOffset());
}
if (renderable->getNormalOffset() != -1
&& shader->hasHandle(Shader::NORMAL)) {
glEnableVertexAttribArray(shader->getHandle(Shader::NORMAL));
glVertexAttribPointer(
shader->getHandle(Shader::NORMAL), 3, GL_FLOAT, GL_FALSE,
stride, ((char*) 0) + renderable->getNormalOffset());
}
if (renderable->getUVOffset() != -1 && shader->hasHandle(Shader::UV)) {
glEnableVertexAttribArray(shader->getHandle(Shader::UV));
glVertexAttribPointer(
shader->getHandle(Shader::UV), 2, GL_FLOAT, GL_FALSE,
stride, ((char*) 0) + renderable->getUVOffset());
}
glBindBuffer(GL_ARRAY_BUFFER, 0);
}
else {
return;
}
// Bind cube map.
if (node->hasResource(Resource::CUBE_MAP)
&& shader->hasHandle(Shader::CUBE_MAP)) {
glActiveTexture(GL_TEXTURE0);
CHECK_GL_ERROR("glActiveTexture");
CubeMap* t = static_cast<CubeMap*>(
node->getResource(Resource::CUBE_MAP));
glBindTexture(GL_TEXTURE_CUBE_MAP, t->getId());
CHECK_GL_ERROR("glBindTexture");
glUniform1i(shader->getHandle(Shader::CUBE_MAP), 0);
CHECK_GL_ERROR("glUniform1i");
}
int hTextures[8];
hTextures[0] = glGetUniformLocation(shader->getId(),
SHADER_MAIN_TEXTURE);
// Bind the texture.
vector<Resource*> textures = node->getResources(Resource::TEXTURE_2D);
UINT size = textures.size() < 8 ? textures.size() : 7;
UINT texture = 0;
for (UINT i = 0; i < size; i++) {
texture = i + 1;
const string& name = textures[i]->getName();
Texture2D* tex = static_cast<Texture2D*>(textures[i]);
string textName = name.substr(0, name.length() - 4);
hTextures[texture] = glGetUniformLocation(shader->getId(),
textName.c_str());
if (hTextures[texture] == -1) {
continue;
}
glActiveTexture(GL_TEXTURE0 + i + 1);
CHECK_GL_ERROR("glActiveTexture");
glBindTexture(GL_TEXTURE_2D, tex->getId());
CHECK_GL_ERROR("glBindTexture");
glUniform1i(hTextures[texture], texture);
CHECK_GL_ERROR("glUniform1i");
}
// Render node.
// BoundingVolume* volume = (*model->getBoundingVolumes())[i];
// if (model->hasBoundingVolumes()) {
// if (volume->isInFrustum(services_->getCamera(), node)
// == BoundingVolume::OUTSIDE) {
// continue;
// }
// }
int renderType;
switch (renderable->getRenderType()) {
case Renderable::RENDER_TYPE_POINTS:
renderType = GL_POINTS;
//glPointSize(renderable->getPointSize());
break;
case Renderable::RENDER_TYPE_LINES:
renderType = GL_LINES;
glLineWidth(renderable->getLineWidth());
break;
case Renderable::RENDER_TYPE_TRIANGLE_FAN:
renderType = GL_TRIANGLE_FAN;
break;
case Renderable::RENDER_TYPE_TRIANGLE_STRIP:
renderType = GL_TRIANGLE_STRIP;
break;
default:
renderType = GL_TRIANGLES;
break;
}
if (renderable->getWindingType() == Renderable::WINDING_TYPE_CCW) {
glFrontFace(GL_CCW);
}
else {
glFrontFace(GL_CW);
}
if (renderable->getCullFace()) {
glEnable(GL_CULL_FACE);
}
else {
glDisable(GL_CULL_FACE);
}
UINT renderCount = renderable->getRenderCount();
int lastTexture = 0;
for (UINT i = 0; i < renderable->getRenderCount(); i++) {
renderable->setRenderable(i);
// Ambient material color.
if (shader->hasHandle(Shader::AMBIENT)) {
shader->setVector3(Shader::AMBIENT,
renderable->getAmbient().toArray());
}
// Diffuse material color.
if (shader->hasHandle(Shader::DIFFUSE)) {
shader->setVector3(Shader::DIFFUSE,
renderable->getDiffuse().toArray());
}
// Specular material color.
if (shader->hasHandle(Shader::SPECULAR)) {
shader->setVector3(Shader::SPECULAR,
renderable->getSpecular().toArray());
}
// Specular material color intensity.
shader->setFloat(Shader::SPECULARITY, renderable->getSpecularity());
// Model transparency.
shader->setFloat(Shader::TRANSPARENCY, renderable->getTransparency());
// Bind main texture.
if (renderable->getTexture() != lastTexture
&& hTextures[0] != -1) {
lastTexture = renderable->getTexture();
if (shader->hasHandle(Shader::MAIN_TEXTURE)) {
if (lastTexture == 0) {
shader->setFloat(Shader::MAIN_TEXTURE, 0.0f);
}
else {
shader->setFloat(Shader::MAIN_TEXTURE, 1.0f);
}
}
glActiveTexture(GL_TEXTURE0);
CHECK_GL_ERROR("glActiveTexture");
glBindTexture(GL_TEXTURE_2D, renderable->getTexture());
CHECK_GL_ERROR("glBindTexture");
glUniform1i(hTextures[0], 0);
CHECK_GL_ERROR("glUniform1i");
}
if (renderable->getIBO() > 0) {
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER,
renderable->getIBO());
if (renderable->getIndexType() ==
Renderable::INDEX_TYPE_USHORT) {
glDrawElements(renderType,
renderable->getIndexCount(),
GL_UNSIGNED_SHORT,
0);
CHECK_GL_ERROR("glDrawElements");
}
else {
glDrawElements(renderType,
renderable->getIndexCount(),
GL_UNSIGNED_INT,
0);
CHECK_GL_ERROR("glDrawElementsInt");
}
}
else {
glDrawArrays(renderType, 0, renderable->getVertexCount() / 3);
CHECK_GL_ERROR("glDrawArrays");
}
}
//// Unbind the cube map.
//if (node->hasResource(Resource::CUBE_MAP)) {
// glBindTexture(GL_TEXTURE_CUBE_MAP, 0);
//}
//// Unbind the textures.
//for (UINT i = 0; i < 8; i++) {
// glActiveTexture(GL_TEXTURE0 + i);
// CHECK_GL_ERROR("glActiveTexture");
// glBindTexture(GL_TEXTURE_2D, 0);
//}
}