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Implement batched rendering in OpenGL
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@JoelOtter
JoelOtter committed Mar 11, 2024
1 parent 633327c commit 78898c9
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Showing 4 changed files with 201 additions and 99 deletions.
264 changes: 170 additions & 94 deletions src/plugins/opengl/src/opengl_batch.cpp
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Original file line number Diff line number Diff line change
Expand Up @@ -8,6 +8,7 @@
#include "growl/core/graphics/window.h"
#include "opengl_shader.h"
#include "opengl_texture.h"
#include <OpenGL/OpenGL.h>
#include <cmath>
#include <vector>

Expand Down Expand Up @@ -36,7 +37,8 @@ OpenGLBatch::OpenGLBatch(
glGenBuffers(1, &ubo);
glBindBuffer(GL_UNIFORM_BUFFER, ubo);
glBufferData(
GL_UNIFORM_BUFFER, 2 * sizeof(glm::mat4), NULL, GL_STATIC_DRAW);
GL_UNIFORM_BUFFER, (MAX_BATCH_SIZE + 1) * sizeof(glm::mat4), NULL,
GL_STATIC_DRAW);
glBindBuffer(GL_UNIFORM_BUFFER, 0);
}

Expand Down Expand Up @@ -68,9 +70,11 @@ void OpenGLBatch::begin() {
glBindBufferRange(GL_UNIFORM_BUFFER, 0, ubo, 0, sizeof(glm::mat4));
glBufferSubData(
GL_UNIFORM_BUFFER, 0, sizeof(glm::mat4), glm::value_ptr(projection));
glBindBuffer(GL_UNIFORM_BUFFER, 0);
}

void OpenGLBatch::end() {
flush();
glBindVertexArray(0);
if (fbo) {
glBindFramebuffer(GL_FRAMEBUFFER, 0);
Expand All @@ -81,82 +85,106 @@ void OpenGLBatch::setColor(float r, float g, float b, float a) {
color = {r, g, b, a};
}

void OpenGLBatch::setTransform(glm::mat4x4 transform) {
glBindBuffer(GL_UNIFORM_BUFFER, ubo);
glBufferSubData(
GL_UNIFORM_BUFFER, sizeof(glm::mat4), sizeof(glm::mat4),
glm::value_ptr(transform));
glBindBuffer(GL_UNIFORM_BUFFER, 0);
}

void OpenGLBatch::draw(
const Texture& texture, float x, float y, float width, float height,
glm::mat4x4 transform) {
auto& tex = static_cast<const OpenGLTexture&>(texture);
tex.bind();
setTransform(transform);
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
glEnable(GL_BLEND);
if (&tex != bound_tex || default_shader != bound_shader) {
flush();
}
uniforms.insert(uniforms.end(), SpriteBlock{transform});
bound_tex = &tex;
bound_shader = default_shader;
float right = x + width;
float bottom = y + height;
float quad_vertex_data[] = {
x, y, 0.0f, 0.0f, // Top-left
right, y, 1.0f, 0.0f, // Top-right
right, bottom, 1.0f, 1.0f, // Bottom-right
x, bottom, 0.0f, 1.0f // Bottom-left
};
GLuint elements[] = {0, 1, 2, 2, 3, 0};
glBindBuffer(GL_ARRAY_BUFFER, vbo);
glBufferData(
GL_ARRAY_BUFFER, sizeof(quad_vertex_data), quad_vertex_data,
GL_STATIC_DRAW);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, ebo);
glBufferData(
GL_ELEMENT_ARRAY_BUFFER, sizeof(elements), elements, GL_STATIC_DRAW);
default_shader->bind(color);
glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);
vertices.insert(
vertices.end(), {
x,
y,
0.0f,
0.0f,
static_cast<GLfloat>(idx), // Top-left
right,
y,
1.0f,
0.0f,
static_cast<GLfloat>(idx), // Top-right
right,
bottom,
1.0f,
1.0f,
static_cast<GLfloat>(idx), // Bottom-right
x,
bottom,
0.0f,
1.0f,
static_cast<GLfloat>(idx) // Bottom-left
});
elements.insert(
elements.end(),
{verts, verts + 1, verts + 2, verts + 2, verts + 3, verts});
idx++;
verts += 4;
}

void OpenGLBatch::draw(
const TextureAtlasRegion& region, float x, float y, float width,
float height, glm::mat4x4 transform) {
auto& tex = static_cast<const OpenGLTexture&>(region.atlas->getTexture());
tex.bind();
setTransform(transform);
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
glEnable(GL_BLEND);
if (&tex != bound_tex || default_shader != bound_shader) {
flush();
}
uniforms.insert(uniforms.end(), SpriteBlock{transform});
bound_tex = &tex;
bound_shader = default_shader;
float right = x + width;
float bottom = y + height;
float quad_vertex_data[] = {
x, y, region.region.u0, region.region.v0,
right, y, region.region.u1, region.region.v0,
right, bottom, region.region.u1, region.region.v1,
x, bottom, region.region.u0, region.region.v1};
GLuint elements[] = {0, 1, 2, 2, 3, 0};
glBindBuffer(GL_ARRAY_BUFFER, vbo);
glBufferData(
GL_ARRAY_BUFFER, sizeof(quad_vertex_data), quad_vertex_data,
GL_STATIC_DRAW);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, ebo);
glBufferData(
GL_ELEMENT_ARRAY_BUFFER, sizeof(elements), elements, GL_STATIC_DRAW);
default_shader->bind(color);
glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);
vertices.insert(
vertices.end(), {
x,
y,
region.region.u0,
region.region.v0,
static_cast<GLfloat>(idx),
right,
y,
region.region.u1,
region.region.v0,
static_cast<GLfloat>(idx),
right,
bottom,
region.region.u1,
region.region.v1,
static_cast<GLfloat>(idx),
x,
bottom,
region.region.u0,
region.region.v1,
static_cast<GLfloat>(idx),
});
elements.insert(
elements.end(),
{verts, verts + 1, verts + 2, verts + 2, verts + 3, verts});
idx++;
verts += 4;
}

void OpenGLBatch::draw(
const GlyphLayout& glyph_layout, const FontTextureAtlas& font_texture_atlas,
float x, float y, glm::mat4x4 transform) {
auto& tex =
static_cast<const OpenGLTexture&>(font_texture_atlas.getTexture());
tex.bind();
setTransform(transform);
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
glEnable(GL_BLEND);
auto shader = font_texture_atlas.getType() == FontFaceType::MSDF
? sdf_shader
: default_shader;
if (&tex != bound_tex || shader != bound_shader) {
flush();
}
uniforms.insert(uniforms.end(), SpriteBlock{transform});
bound_tex = &tex;
bound_shader = shader;

std::vector<float> vertices;
std::vector<GLuint> indices;
GLuint i = 0;
GLuint i = verts;
for (auto& glyph : glyph_layout.getLayout()) {
float gx = std::round(x + glyph.x);
float gy = std::round(y + glyph.y);
Expand All @@ -172,28 +200,16 @@ void OpenGLBatch::draw(
auto& region = region_result.get();

vertices.insert(
vertices.end(), {gx, gy, region.u0, region.v0, right, gy, region.u1,
region.v0, right, bottom, region.u1, region.v1, gx,
bottom, region.u0, region.v1});
indices.insert(indices.end(), {i, i + 1, i + 2, i + 2, i + 3, i});
vertices.end(),
{gx, gy, region.u0, region.v0, static_cast<GLfloat>(idx),
right, gy, region.u1, region.v0, static_cast<GLfloat>(idx),
right, bottom, region.u1, region.v1, static_cast<GLfloat>(idx),
gx, bottom, region.u0, region.v1, static_cast<GLfloat>(idx)});
elements.insert(elements.end(), {i, i + 1, i + 2, i + 2, i + 3, i});
i += 4;
verts = i;
}

glBindBuffer(GL_ARRAY_BUFFER, vbo);
glBufferData(
GL_ARRAY_BUFFER, vertices.size() * sizeof(float), vertices.data(),
GL_STATIC_DRAW);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, ebo);
glBufferData(
GL_ELEMENT_ARRAY_BUFFER, indices.size() * sizeof(GLuint),
indices.data(), GL_STATIC_DRAW);
if (font_texture_atlas.getType() == FontFaceType::MSDF) {
sdf_shader->bind(color);
} else {
default_shader->bind(color);
}
glDrawElements(
GL_TRIANGLES, static_cast<GLsizei>(indices.size()), GL_UNSIGNED_INT, 0);
idx++;
}

void OpenGLBatch::drawRect(
Expand All @@ -204,28 +220,45 @@ void OpenGLBatch::drawRect(
void OpenGLBatch::drawRect(
float x, float y, float width, float height, Shader& shader,
glm::mat4x4 transform) {
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
glEnable(GL_BLEND);
setTransform(transform);

auto& gl_shader = static_cast<OpenGLShader&>(shader);
uniforms.insert(uniforms.end(), SpriteBlock{transform});

if (bound_tex || bound_shader != &gl_shader) {
flush();
}
bound_shader = &gl_shader;

float right = x + width;
float bottom = y + height;
float quad_vertex_data[] = {
x, y, 0.0f, 0.0f, // Top-left
right, y, 1.0f, 0.0f, // Top-right
right, bottom, 1.0f, 1.0f, // Bottom-right
x, bottom, 0.0f, 1.0f // Bottom-left
};
GLuint elements[] = {0, 1, 2, 2, 3, 0};
glBindBuffer(GL_ARRAY_BUFFER, vbo);
glBufferData(
GL_ARRAY_BUFFER, sizeof(quad_vertex_data), quad_vertex_data,
GL_STATIC_DRAW);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, ebo);
glBufferData(
GL_ELEMENT_ARRAY_BUFFER, sizeof(elements), elements, GL_STATIC_DRAW);
static_cast<OpenGLShader&>(shader).bind(color);
glDrawElements(GL_TRIANGLES, 6, GL_UNSIGNED_INT, 0);
vertices.insert(
vertices.end(), {
x,
y,
0.0f,
0.0f,
static_cast<GLfloat>(idx), // Top-left
right,
y,
1.0f,
0.0f,
static_cast<GLfloat>(idx), // Top-right
right,
bottom,
1.0f,
1.0f,
static_cast<GLfloat>(idx), // Bottom-right
x,
bottom,
0.0f,
1.0f,
static_cast<GLfloat>(idx) // Bottom-left
});
elements.insert(
elements.end(),
{verts, verts + 1, verts + 2, verts + 2, verts + 3, verts});
verts += 4;
idx++;
}

int OpenGLBatch::getTargetWidth() {
Expand All @@ -235,3 +268,46 @@ int OpenGLBatch::getTargetWidth() {
int OpenGLBatch::getTargetHeight() {
return height;
}

void OpenGLBatch::flush() {
if (!idx) {
return;
}

glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA);
glEnable(GL_BLEND);

glBindBuffer(GL_ARRAY_BUFFER, vbo);
glBufferData(
GL_ARRAY_BUFFER, vertices.size() * sizeof(GLfloat), vertices.data(),
GL_STATIC_DRAW);
glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, ebo);
glBufferData(
GL_ELEMENT_ARRAY_BUFFER, elements.size() * sizeof(GLuint),
elements.data(), GL_STATIC_DRAW);

if (uniforms.size()) {
glBindBuffer(GL_UNIFORM_BUFFER, ubo);
glBufferSubData(
GL_UNIFORM_BUFFER, sizeof(glm::mat4),
sizeof(SpriteBlock) * uniforms.size(), uniforms.data());
glBindBuffer(GL_UNIFORM_BUFFER, 0);
}

if (bound_tex) {
bound_tex->bind();
}
if (bound_shader) {
bound_shader->bind(color);
}

glDrawElements(GL_TRIANGLES, elements.size(), GL_UNSIGNED_INT, 0);

idx = 0;
verts = 0;
vertices.clear();
elements.clear();
uniforms.clear();
bound_tex = nullptr;
bound_shader = nullptr;
}
15 changes: 14 additions & 1 deletion src/plugins/opengl/src/opengl_batch.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -9,11 +9,16 @@ namespace Growl {

class Window;
class OpenGLShader;
class OpenGLTexture;
class FontTextureAtlas;
class GlyphLayout;
class Texture;
struct TextureAtlasRegion;

struct SpriteBlock {
glm::mat4x4 transform;
};

class OpenGLBatch : public Batch {
public:
OpenGLBatch(
Expand Down Expand Up @@ -63,7 +68,15 @@ class OpenGLBatch : public Batch {
GLuint fbo = 0;
GLuint ubo = 0;

void setTransform(glm::mat4x4 transform);
unsigned int idx = 0;
unsigned int verts = 0;
const OpenGLTexture* bound_tex = nullptr;
OpenGLShader* bound_shader = nullptr;
std::vector<GLfloat> vertices;
std::vector<GLuint> elements;
std::vector<SpriteBlock> uniforms;

void flush();
};

} // namespace Growl
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