glMultiDrawIndirect和DrawElementsIndirectCommands无法呈现所有对象 [英] glMultiDrawIndirect and DrawElementsIndirectCommands not rendering all objects
问题描述
我似乎错误地使用了 glMultiDrawIndirect (MDI)和/或 DrawElementsIndirectCommand (DEIC)，因为我无法正确呈现所有对象.尝试对相似的对象重复使用绘制命令的方法&纹理(实例化" ... ish)在所有位置绘制所有对象. 调试"方法仅对每个对象(两个三角形)使用1个绘制命令，但输出始终是对象太少，第一个对象的位置永远不会用于任何对象.
I appear to be using glMultiDrawIndirect (MDI) and/or DrawElementsIndirectCommand (DEIC) incorrectly as I am not able to render all objects correctly. The method attempting to reuse draw commands for similar objects & textures ('instancing'...ish), draws all object in all locations. The 'debug' method simply uses 1 draw command per object (two triangles), but the output is always too few objects, with the first object's location never being used for any object.
使用实例化失败的尝试时会发生以下情况:
This is what happens when using the failed attempt at instancing:
使用每个DEIC的一个对象(两个三角形)的调试"方法时，会发生以下情况:
This is what happens when using the 'debug' method of one object (two triangles) per DEIC:
目标是正确使用DEIC中的instanceCount，以允许实例化，同时在正确的位置绘制正确数量的对象.我在Google突袭中的冒险经历表明，如果DEIC存储在缓冲区中，则DEIC 的baseInstance字段可以用作drawID.如果这是不可能的，或者如果我对用途有极大的误解，请给我打电话，让我知道！我已尝试包括最少数量的适用代码，以避免发布10,000个字数的邮件.
The goal would be to correctly use the instanceCount in DEIC to allow for something approaching instancing, while drawing the correct number of objects in the correct locations. My adventures in google-raiding has suggested that the baseInstance field of the DEIC could be used as the drawID if the DEICs are stored in a buffer. If this is impossible or if I am vastly misunderstanding the uses, please call me out and let me know! I have tried to include the smallest amount of applicable code to avoid a 10,000 word count post.
下面，我正在创建绘制路径"对象，这些对象是要加载到缓冲区中的缓冲区ID和向量的集合(基于与此问题无关的众多变量).
Below, I am creating "draw path" objects that are a collection of buffer IDs and vectors to be loaded into buffers (based on numerous variables unrelated to this question).
// VAO
glGenVertexArrays(1, &p->vertexArrayObject);
glBindVertexArray(p->vertexArrayObject);
// vertices
glCreateBuffers(1, &p->vertexBuffer);
glBindVertexBuffer(bindingIndex, p->vertexBuffer, 0, sizeof(Vertex));
glEnableVertexArrayAttrib(p->vertexArrayObject, 0);
glEnableVertexArrayAttrib(p->vertexArrayObject, 1);
glVertexAttribFormat(0, 3, GL_FLOAT, GL_FALSE, offsetof(Vertex, position));
glVertexAttribBinding(0, bindingIndex);
glVertexAttribFormat(1, 2, GL_FLOAT, GL_TRUE, offsetof(Vertex, uv));
glVertexAttribBinding(1, bindingIndex);
if(p->pathType == DrawPathType::FAST)
{
glNamedBufferStorage(p->vertexBuffer, p->rbVertices.bufferSize, nullptr, m_persistentCreateFlags);
p->rbVertices.ptr = (Vertex*)glMapNamedBufferRange(p->vertexBuffer, 0, p->rbVertices.bufferSize, m_persistentMapFlags);
p->rbVertices.bufferFragment = p->rbVertices.bufferSize / 3;
}
// indices
glCreateBuffers(1, &p->indexBuffer);
glVertexArrayElementBuffer(p->vertexArrayObject, p->indexBuffer);
// draw commands
// glCreateBuffers(1, &p->drawCmdBuffer);
// glBindBuffer(GL_DRAW_INDIRECT_BUFFER, p->drawCmdBuffer);
// glNamedBufferStorage(p->drawCmdBuffer, p->rbCommands.bufferSize, nullptr, m_persistentCreateFlags);
// p->rbCommands.ptr = (DEIC*)glMapNamedBufferRange(p->drawCmdBuffer, 0, p->rbCommands.bufferSize, m_persistentMapFlags);
// p->rbCommands.bufferFragment = p->rbCommands.bufferSize / 3;
// unsure how this works
// glEnableVertexArrayAttrib(p->vertexArrayObject, 2);
// glVertexAttribIFormat(2, 1, GL_UNSIGNED_INT, offsetof(DrawElementsIndirectCommand, baseInstance));
// glVertexAttribBinding(2, bindingIndex);
// glVertexBindingDivisor(bindingIndex, 1);
// draw IDs
glCreateBuffers(1, &p->drawIDBuffer);
glBindBuffer(GL_ARRAY_BUFFER, p->drawIDBuffer);
glEnableVertexAttribArray(2);
glVertexAttribIPointer(2, 1, GL_UNSIGNED_INT, sizeof(GLuint), 0);
glVertexAttribDivisor(2, 1);
// transforms
glCreateBuffers(1, &p->transformBuffer);
if(p->pathType == DrawPathType::LONG || p->pathType == DrawPathType::FAST)
{
glNamedBufferStorage(p->transformBuffer, p->rbTransforms.bufferSize, nullptr, m_persistentCreateFlags);
p->rbTransforms.ptr = (glm::mat4*)glMapNamedBufferRange(p->transformBuffer, 0, p->rbTransforms.bufferSize, m_persistentMapFlags);
p->rbTransforms.bufferFragment = p->rbTransforms.bufferSize / 3;
glBindBufferBase(GL_SHADER_STORAGE_BUFFER, 0, p->transformBuffer);
}
// texture addresses
glCreateBuffers(1, &p->textureAddressBuffer);
glBindBufferBase(GL_SHADER_STORAGE_BUFFER, 1, p->textureAddressBuffer);
这是"renderPrep"功能的有用部分.
This is the useful part of the 'renderPrep' function.
for(size_t i = 0; i < glyphs->size(); i++)
{
auto it = glyphs->at(i);
// ensure we have a valid texture address
if(!it->textureAddress.defined())
{
Logger::getInstance().Log(Logs::CRIT, Logs::Drawing, "Renderer2D::drawPrep()", "Iteration [{}] of [{}] has a null texture address (0,0)!", i, glyphs->size());
failed++;
}
else
{
offset = verts->size();
for(int in = 0; in < QUAD_VERTS; in++) { indices->push_back(baseQuadIndices[in] + offset); }
// creating our model space to world space matrix ('model' in "projection * view * model")
glm::mat4 transRotate = glm::rotate(identMat, glm::radians(it->angle), glm::vec3(0.0f, 0.0f, 1.0f));
transforms->push_back(transRotate);
transforms->back() = glm::translate(transforms->back(), it->position);
// push back modelspace vertices
for(auto& v : it->vertices) { verts->push_back(v); }
// update previous draw command or create a new one
if(currentTex.exists() && currentTex == it->textureAddress)
{
// append previous draw command
DEICs->back().vertexCount += QUAD_VERTS;
DEICs->back().instanceCount += 1; // two triangles, thus two instances
}
else
{
// different texture, new draw command
DEIC tmp = { QUAD_VERTS, 1, (inc * QUAD_VERTS), (inc * BASE_VERTS), inc };
DEICs->push_back(tmp);
currentTex = it->textureAddress;
}
/// \NOTE: Current issue is that the draw command is only drawing one object, in two iterations.
/// This is responsible for the blank second box
/* DEIC tmp = { QUAD_VERTS, 1, (inc * QUAD_VERTS), (inc * BASE_VERTS), 0 };
DEICs->push_back(tmp);
texAddrs->push_back(it->textureAddress); */
Logger::getInstance().Log(Logs::DEBUG, Logs::Drawing, "Renderer2D::drawPrep()",
"\n\033[93mDEIC #{}\033[0m:\n\tvertCount\t\t{}\n\tinstCount\t\t{}\n\tfirstInd\t\t{}\n\tbaseVert\t\t{}\n\tbaseInst\t\t{}\n",
DEICs->size(), DEICs->back().vertexCount, DEICs->back().instanceCount, DEICs->back().firstIndex, DEICs->back().baseVertex, DEICs->back().baseInstance);
texAddrs->push_back(currentTex);
p->drawIDs.push_back(inc);
inc++;
}
}
这是实际上负责渲染的代码段.
This is the snippet actually responsible for rendering.
int activeProgramID = 0; // currently used glsl program
glGetIntegerv(GL_CURRENT_PROGRAM, &activeProgramID);
// active passed glsl program id, or enable existing if not already enabled
if(glProgID > 0) { glUseProgram(glProgID); }
else if(activeProgramID == 0) { glUseProgram(m_prog->getProgramID()); }
// all clear, do it!
glBindVertexArray(p->vertexArrayObject);
// bind SSBOs, if applicable
if(p->transformBuffer) { glBindBufferBase(GL_SHADER_STORAGE_BUFFER, 0, p->transformBuffer); }
if(p->textureAddressBuffer) { glBindBufferBase(GL_SHADER_STORAGE_BUFFER, 1, p->textureAddressBuffer); }
// finally render
//if(p->drawCmdBuffer) { glBindBuffer(GL_DRAW_INDIRECT_BUFFER, p->drawCmdBuffer); glMultiDrawElementsIndirect(GL_TRIANGLES, GL_UNSIGNED_INT, 0, p->drawCommands.size(), 0); }
//else { glMultiDrawElementsIndirect(GL_TRIANGLES, GL_UNSIGNED_INT, p->drawCommands.data(), p->drawCommands.size(), 0); }
glMultiDrawElementsIndirect(GL_TRIANGLES, GL_UNSIGNED_INT, p->drawCommands.data(), p->drawCommands.size(), 0);
// update ring buffer(s), if applicable
if(p->rbCommands.ptr != nullptr) { m_bufferLockManager->lockRange(p->rbCommands.oldHead, p->rbCommands.bufferFragment); }
if(p->rbTransforms.ptr != nullptr) { m_bufferLockManager->lockRange(p->rbTransforms.oldHead, p->rbTransforms.bufferFragment); }
if(p->rbVertices.ptr != nullptr) { m_bufferLockManager->lockRange(p->rbVertices.oldHead, p->rbVertices.bufferFragment); }
// options specific to a "fast" draw path (if a fast draw path, glyphs are single use)
if(p->pathType == DrawPathType::FAST) { p->clear(true); }
// clean up
glBindVertexArray(0);
// change to previous glProgram
if(activeProgramID) { glUseProgram(activeProgramID); }
else { glUseProgram(0); }
编辑#1，2019-04-05 11:53a EST :
首先，我忘记了着色器！很抱歉错过这个机会.
First, I forgot shaders! Apologies for missing this.
// --------- Vertex shader ------------
// uniforms / shader_storage_buffer object
layout(std140, binding = 0) buffer CB0 { mat4 Transforms[]; };
// view & projection in one
uniform mat4 ViewProjection;
// input
layout(location = 0) in vec3 In_v3Pos;
layout(location = 1) in vec2 In_v2TexCoord;
layout(location = 2) in uint In_uiDrawID;
// output
out DrawBlock
{
vec2 v2TexCoord;
flat uint iDrawID;
} Out;
void main()
{
mat4 World = Transforms[In_uiDrawID + gl_InstanceID];
vec4 worldPos = World * vec4(In_v3Pos, 1.0);
gl_Position = ViewProjection * worldPos;
Out.v2TexCoord = In_v2TexCoord;
Out.iDrawID = In_uiDrawID;
}
// --------- Fragment shader ------------
struct TexAddress
{
sampler2DArray arr;
float slice;
};
layout (std430, binding = 1) buffer CB1 { TexAddress texAddress[]; };
// input
in DrawBlock
{
vec2 v2TexCoord;
flat uint iDrawID;
} In;
// output
layout(location = 0) out vec4 Out_v4Color;
vec4 Texture(TexAddress addr, vec2 uv) { return texture(addr.arr, vec3(uv, addr.slice)); }
void main()
{
int DrawID = int(In.iDrawID);
Out_v4Color = vec4(Texture(texAddress[DrawID], In.v2TexCoord).xyz, 1.0f);
}
如果我使用非DSA删除了drawIDs块并替换为下面的代码段，则会绘制白色三角形，重点放在屏幕中心.
If I removed the drawIDs block using non-DSA and replace with the snippet below, it draws white triangles focusing on the center of the screen.
glCreateBuffers(1, &p->drawCmdBuffer);
glBindBuffer(GL_DRAW_INDIRECT_BUFFER, p->drawCmdBuffer);
glNamedBufferStorage(p->drawCmdBuffer, p->rbCommands.bufferSize, nullptr, m_persistentCreateFlags);
p->rbCommands.ptr = (DEIC*)glMapNamedBufferRange(p->drawCmdBuffer, 0, p->rbCommands.bufferSize, m_persistentMapFlags);
p->rbCommands.bufferFragment = p->rbCommands.bufferSize / 3;
glEnableVertexArrayAttrib(p->vertexArrayObject, 2);
glVertexAttribIFormat(2, 1, GL_UNSIGNED_INT, offsetof(DrawElementsIndirectCommand, baseInstance));
glVertexAttribBinding(2, bindingIndex);
glVertexBindingDivisor(2, 1);
结果:
编辑#2 @ 2019-04-06 12:09p EST :在github上创建了具有渲染器完整标题/源的要点.链接: https://gist.github.com/bbilyeu/bbf74ef4eaf979b5d2b4f2c2a9dcce48
EDIT #2 @ 2019-04-06 12:09p EST: Created a gist on github with the full header/source for the renderer. Link : https://gist.github.com/bbilyeu/bbf74ef4eaf979b5d2b4f2c2a9dcce48
推荐答案
元素，实例和绘制命令的数量均不同，并且引用的事物也不同.特别是，使用任何多绘制命令并不一定意味着您要进行任何实例化.
The number of elements, instances and draw commands are all different, and refer to different things. In particular, using any multi-draw command does not necessarily mean that you do any instancing.
以下代码使用一个 glMultiDrawArraysIndirect调用发出两个绘图命令:
The following code uses one glMultiDrawArraysIndirect call to issue two drawing commands:
- 呈现"quad"对象的三个实例
- 渲染三角形"对象的五个实例
- Render three instances of the "quad" object
- Render five instances of the "triangle" object
数据
struct Vert {
vec2f position;
};
struct Inst {
box2f position;
vec4f color;
};
static const Vert verts[] = {
// quad
{ { 0, 0 } }, // vertex 0
{ { 1, 0 } },
{ { 0, 1 } },
{ { 1, 1 } },
// triangle
{ { 0, 0 } }, // vertex 4
{ { 1, 0 } },
{ { 0.5, 1 } },
};
static const Inst insts[] = {
// three quads
{ { -0.8, -0.8, -0.6, -0.6 }, { 1, 0, 0, 1 } }, // instance 0
{ { -0.1, -0.8, 0.1, -0.6 }, { 0, 1, 0, 1 } },
{ { 0.6, -0.8, 0.8, -0.6 }, { 0, 0, 1, 1 } },
// five triangles
{ { -0.8, 0.6, -0.6, 0.8 }, { 1, 1, 0, 1 } }, // instance 3
{ { -0.4, 0.6, -0.2, 0.8 }, { 0.1, 0.1, 0.1, 1 } },
{ { -0.1, 0.6, 0.1, 0.8 }, { 0, 1, 1, 1 } },
{ { 0.2, 0.6, 0.4, 0.8 }, { 0.1, 0.1, 0.1, 1 } },
{ { 0.6, 0.6, 0.8, 0.8 }, { 1, 0, 1, 1 } },
};
static const DrawArraysIndirectCommandSN cmds[] = {
// quads: 4 vertices, 3 instances, first vertex=0, first instance=0
{ 4, 3, 0, 0 },
// triangles: 3 vertices, 5 instances, first vertex=4, first instance=3
{ 3, 5, 4, 3 },
};
初始化代码:
GLuint buf[3]; // vertex, instance, draw-command buffers
glCreateBuffers(3, buf);
glNamedBufferStorage(buf[0], sizeof(verts), verts, 0);
glNamedBufferStorage(buf[1], sizeof(insts), insts, 0);
glNamedBufferStorage(buf[2], sizeof(cmds), cmds, 0);
GLuint va;
glCreateVertexArrays(1, &va);
glVertexArrayVertexBuffer(va, 0, buf[0], 0, sizeof(Vert));
glVertexArrayVertexBuffer(va, 1, buf[1], 0, sizeof(Inst));
glVertexArrayBindingDivisor(va, 1, 1);
glVertexArrayAttribBinding(va, 0, 0);
glEnableVertexArrayAttrib(va, 0);
glVertexArrayAttribFormat(va, 0, 2, GL_FLOAT, 0, offsetof(Vert, position));
glVertexArrayAttribBinding(va, 1, 1);
glEnableVertexArrayAttrib(va, 1);
glVertexArrayAttribFormat(va, 1, 4, GL_FLOAT, 0, offsetof(Inst, position));
glVertexArrayAttribBinding(va, 2, 1);
glEnableVertexArrayAttrib(va, 2);
glVertexArrayAttribFormat(va, 2, 4, GL_FLOAT, 0, offsetof(Inst, color));
渲染部分:
glClear(GL_COLOR_BUFFER_BIT);
glBindProgramPipeline(pp.get());
glBindVertexArray(va);
glBindBuffer(GL_DRAW_INDIRECT_BUFFER, buf[2]);
glMultiDrawArraysIndirect(GL_TRIANGLE_STRIP, 0, sizeof(cmds)/sizeof(cmds[0]), 0);
顶点着色器:
#version 450 core
layout(location = 0) in vec2 position;
layout(location = 1) in vec4 inst_position;
layout(location = 2) in vec4 color;
out gl_PerVertex {
vec4 gl_Position;
};
layout(location = 0) out PerVertex {
vec4 color;
} OUT;
void main() {
OUT.color = color;
gl_Position = vec4(mix(inst_position.xy, inst_position.zw, position), 0, 1);
}
片段着色器:
#version 450 core
layout(location = 0) in PerVertex {
vec4 color;
} IN;
layout(location = 0) out vec4 OUT;
void main() {
OUT = IN.color;
}
结果:
这篇关于glMultiDrawIndirect和DrawElementsIndirectCommands无法呈现所有对象的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
