LookingGlass/client/renderers/opengl.c

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#include "lg-renderer.h"
#include <stdint.h>
#include <stdbool.h>
#define GL_GLEXT_PROTOTYPES
#include <GL/gl.h>
#include <GL/glu.h>
#include "debug.h"
#include "memcpySSE.h"
#define VBO_BUFFERS 2
struct LGR_OpenGL
{
bool initialized;
LG_RendererFormat format;
GLuint intFormat;
GLuint vboFormat;
size_t texSize;
bool hasBuffers;
GLuint vboID[VBO_BUFFERS];
uint8_t * texPixels[VBO_BUFFERS];
int texIndex;
bool hasTextures;
GLuint vboTex[VBO_BUFFERS];
};
bool lgr_opengl_check_error(const char * name)
{
GLenum error = glGetError();
if (error == GL_NO_ERROR)
return false;
const GLubyte * errStr = gluErrorString(error);
DEBUG_ERROR("%s = %d (%s)", name, error, errStr);
return true;
}
const char * lgr_opengl_get_name()
{
return "OpenGL";
}
bool lgr_opengl_initialize(void ** opaque, const LG_RendererParams params, const LG_RendererFormat format)
{
// check if the GPU supports GL_ARB_buffer_storage first
// there is no advantage to this renderer if it is not present.
const GLubyte * extensions = glGetString(GL_EXTENSIONS);
if (!gluCheckExtension((const GLubyte *)"GL_ARB_buffer_storage", extensions))
{
DEBUG_INFO("The GPU doesn't support GL_ARB_buffer_storage");
return false;
}
// create our local storage
*opaque = malloc(sizeof(struct LGR_OpenGL));
if (!*opaque)
{
DEBUG_INFO("Failed to allocate %lu bytes", sizeof(struct LGR_OpenGL));
return false;
}
memset(*opaque, 0, sizeof(struct LGR_OpenGL));
struct LGR_OpenGL * this = (struct LGR_OpenGL *)*opaque;
// assume 24 and 32 bit formats are RGB and RGBA
switch(format.bpp)
{
case 24:
this->intFormat = GL_RGB8;
this->vboFormat = GL_BGR;
break;
case 32:
this->intFormat = GL_RGBA8;
this->vboFormat = GL_BGRA;
break;
default:
DEBUG_INFO("%d bpp not supported", format.bpp);
return false;
}
// calculate the texture size in bytes
this->texSize = format.height * format.pitch;
// generate the pixel unpack buffers
glGenBuffers(VBO_BUFFERS, this->vboID);
if (lgr_opengl_check_error("glGenBuffers"))
return false;
this->hasBuffers = true;
// persistant bind the buffers
for (int i = 0; i < VBO_BUFFERS; ++i)
{
glBindBuffer(GL_PIXEL_UNPACK_BUFFER, this->vboID[i]);
if (lgr_opengl_check_error("glBindBuffer"))
return false;
glBufferStorage(GL_PIXEL_UNPACK_BUFFER, this->texSize, 0, GL_MAP_WRITE_BIT | GL_MAP_PERSISTENT_BIT);
if (lgr_opengl_check_error("glBufferStorage"))
return false;
this->texPixels[i] = glMapBufferRange(GL_PIXEL_UNPACK_BUFFER, 0, this->texSize,
GL_MAP_WRITE_BIT | GL_MAP_PERSISTENT_BIT | GL_MAP_FLUSH_EXPLICIT_BIT);
if (lgr_opengl_check_error("glMapBufferRange"))
return false;
if (!this->texPixels[i])
{
DEBUG_ERROR("Failed to map the buffer range");
return false;
}
glBindBuffer(GL_PIXEL_UNPACK_BUFFER, 0);
}
// create the textures
glGenTextures(VBO_BUFFERS, this->vboTex);
if (lgr_opengl_check_error("glGenTextures"))
return false;
this->hasTextures = true;
// bind the textures to the unpack buffers
for (int i = 0; i < VBO_BUFFERS; ++i)
{
glBindTexture(GL_TEXTURE_2D, this->vboTex[i]);
if (lgr_opengl_check_error("glBindTexture"))
return false;
glTexImage2D(
GL_TEXTURE_2D,
0,
this->intFormat,
format.width, format.height,
0,
this->vboFormat,
GL_UNSIGNED_BYTE,
(void*)0
);
if (lgr_opengl_check_error("glTexImage2D"))
return false;
}
glEnable(GL_TEXTURE_2D);
// copy the format into the local storage
memcpy(&this->format, &format, sizeof(LG_RendererFormat));
this->initialized = true;
return true;
}
void lgr_opengl_deinitialize(void * opaque)
{
struct LGR_OpenGL * this = (struct LGR_OpenGL *)opaque;
if (!this)
return;
if (this->hasTextures)
glDeleteTextures(VBO_BUFFERS, this->vboTex);
if (this->hasBuffers)
glDeleteBuffers(VBO_BUFFERS, this->vboID);
free(this);
}
bool lgr_opengl_is_compatible(void * opaque, const LG_RendererFormat format)
{
const struct LGR_OpenGL * this = (struct LGR_OpenGL *)opaque;
if (!this || !this->initialized)
return false;
return (memcmp(&this->format, &format, sizeof(LG_RendererFormat)) == 0);
}
bool lgr_opengl_render(void * opaque, const LG_RendererRect destRect, const uint8_t * data, bool resample)
{
struct LGR_OpenGL * this = (struct LGR_OpenGL *)opaque;
if (!this || !this->initialized)
return false;
glClear(GL_COLOR_BUFFER_BIT);
// copy the buffer to the texture
memcpySSE(this->texPixels[this->texIndex], data, this->texSize);
glBindBuffer(GL_PIXEL_UNPACK_BUFFER, this->vboID[this->texIndex]);
glFlushMappedBufferRange(GL_PIXEL_UNPACK_BUFFER, 0, this->texSize);
// bind the texture and update it
glBindTexture(GL_TEXTURE_2D , this->vboTex[this->texIndex]);
glPixelStorei(GL_UNPACK_ALIGNMENT , 4 );
glPixelStorei(GL_UNPACK_ROW_LENGTH , this->format.width );
glTexSubImage2D(
GL_TEXTURE_2D,
0,
0, 0,
this->format.width,
this->format.height,
this->vboFormat,
GL_UNSIGNED_BYTE,
(void*)0
);
const bool mipmap = resample && (
(this->format.width != destRect.w) ||
(this->format.height != destRect.h));
// unbind the buffer
glBindBuffer(GL_PIXEL_UNPACK_BUFFER, 0);
// configure the texture
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
if (mipmap)
{
glGenerateMipmap(GL_TEXTURE_2D);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR_MIPMAP_LINEAR);
}
else
{
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
}
// draw the screen
glEnable(GL_TEXTURE_2D);
glBegin(GL_TRIANGLE_STRIP);
glTexCoord2f(0.0f, 0.0f); glVertex2i(destRect.x , destRect.y );
glTexCoord2f(1.0f, 0.0f); glVertex2i(destRect.x + destRect.w, destRect.y );
glTexCoord2f(0.0f, 1.0f); glVertex2i(destRect.x , destRect.y + destRect.h);
glTexCoord2f(1.0f, 1.0f); glVertex2i(destRect.x + destRect.w, destRect.y + destRect.h);
glEnd();
glDisable(GL_TEXTURE_2D);
glBindTexture(GL_TEXTURE_2D, 0);
if (++this->texIndex == VBO_BUFFERS)
this->texIndex = 0;
return true;
}
const LG_Renderer LGR_OpenGL =
{
.get_name = lgr_opengl_get_name,
.initialize = lgr_opengl_initialize,
.deinitialize = lgr_opengl_deinitialize,
.is_compatible = lgr_opengl_is_compatible,
.render = lgr_opengl_render
};