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#include "../modules.h"
#if JIN_MODULES_RENDER
#include "../utils/macros.h"
#include "Shader.h"
namespace jin
{
namespace graphics
{
#include "base.shader.h"
/*
* https://stackoverflow.com/questions/27941496/use-sampler-without-passing-through-value
* The default value of a sampler variable is 0. From the GLSL 3.30 spec,
* section "4.3.5 Uniforms":
*
* The link time initial value is either the value of the variable's
* initializer, if present, or 0 if no initializer is present.Sampler
* types cannot have initializers.
*
* Since a value of 0 means that it's sampling from texture unit 0, it will
* work without ever setting the value as long as you bind your textures to
* unit 0. This is well defined behavior.
*
* Since texture unit 0 is also the default until you call glActiveTexture()
* with a value other than GL_TEXTURE0, it's very common to always use unit
* 0 as long as shaders do not need more than one texture.Which means that
* often times, setting the sampler uniforms is redundant for simple
* applications.
*
* I would still prefer to always set the values.If nothing else, it makes
* it clear to anybody reading your code that you really mean to sample from
* texture unit 0, and did not just forget to set the value.
*/
const int DEFAULT_TEX_UNIT = 0;
/*static*/ JSLProgram* JSLProgram::currentJSLProgram = nullptr;
JSLProgram* JSLProgram::createJSLProgram(const char* program)
{
return new JSLProgram(program);
}
JSLProgram::JSLProgram(const char* program)
: currentTextureUnit(DEFAULT_TEX_UNIT)
{
char* fs = (char*)calloc(1, strlen(program) + SHADER_FORMAT_SIZE);
formatShader(fs, program);
GLuint shader = glCreateShader(GL_FRAGMENT_SHADER);
glShaderSource(shader, 1, (const GLchar**)&fs, NULL);
glCompileShader(shader);
pid = glCreateProgram();
glAttachShader(pid, shader);
glLinkProgram(pid);
free(fs);
}
JSLProgram::~JSLProgram()
{
if (currentJSLProgram == this)
unuse();
}
static inline GLint getMaxTextureUnits()
{
GLint maxTextureUnits = 0;
glGetIntegerv(GL_MAX_TEXTURE_IMAGE_UNITS, &maxTextureUnits);
return maxTextureUnits;
}
void JSLProgram::use()
{
glUseProgram(pid);
currentJSLProgram = this;
bindDefaultTexture();
}
/*static*/ void JSLProgram::unuse()
{
glUseProgram(0);
currentJSLProgram = nullptr;
}
void JSLProgram::bindDefaultTexture()
{
int loc = glGetUniformLocation(pid, default_tex);
glUniform1i(loc, DEFAULT_TEX_UNIT);
}
GLint JSLProgram::claimTextureUnit(const std::string& name)
{
std::map<std::string, GLint>::iterator unit = textureUnits.find(name);
if (unit != textureUnits.end())
return unit->second;
static GLint MAX_TEXTURE_UNITS = getMaxTextureUnits();
if (++currentTextureUnit >= MAX_TEXTURE_UNITS)
return 0;
textureUnits[name] = currentTextureUnit;
return currentTextureUnit;
}
#define checkJSL() \
if (currentJSLProgram != this) \
return
void JSLProgram::sendFloat(const char* variable, float number)
{
checkJSL();
int loc = glGetUniformLocation(pid, variable);
glUniform1f(loc, number);
}
/**
* https://www.douban.com/note/627332677/
* struct TextureUnit
* {
* GLuint targetTexture1D;
* GLuint targetTexture2D;
* GLuint targetTexture3D;
* GLuint targetTextureCube;
* ...
* };
*
* TextureUnit textureUnits[GL_MAX_TEXTURE_IMAGE_UNITS]
* GLuint currentTextureUnit = 0;
*/
void JSLProgram::sendTexture(const char* variable, const Texture* tex)
{
checkJSL();
GLint location = glGetUniformLocation(pid, variable);
if (location == -1)
return;
GLint unit = claimTextureUnit(variable);
if (unit == 0)
{
// TODO: 쳣
return;
}
glUniform1i(location, unit);
glActiveTexture(GL_TEXTURE0 + unit);
glBindTexture(GL_TEXTURE_2D, tex->getTexture());
glActiveTexture(GL_TEXTURE0);
}
void JSLProgram::sendCanvas(const char* variable, const Canvas* canvas)
{
checkJSL();
GLint location = glGetUniformLocation(pid, variable);
if (location == -1)
return;
GLint unit = claimTextureUnit(variable);
if (unit == 0)
{
// TODO: 쳣
return;
}
glUniform1i(location, unit);
glActiveTexture(GL_TEXTURE0 + unit);
glBindTexture(GL_TEXTURE_2D, canvas->getTexture());
glActiveTexture(GL_TEXTURE0);
}
void JSLProgram::sendVec2(const char* name, float x, float y)
{
checkJSL();
int loc = glGetUniformLocation(pid, name);
glUniform2f(loc, x, y);
}
void JSLProgram::sendVec3(const char* name, float x, float y, float z)
{
checkJSL();
int loc = glGetUniformLocation(pid, name);
glUniform3f(loc, x, y, z);
}
void JSLProgram::sendVec4(const char* name, float x, float y, float z, float w)
{
checkJSL();
int loc = glGetUniformLocation(pid, name);
glUniform4f(loc, x, y, z, w);
}
void JSLProgram::sendColor(const char* name, const Color* col)
{
checkJSL();
int loc = glGetUniformLocation(pid, name);
glUniform4f(loc,
col->r / 255.f,
col->g / 255.f,
col->b / 255.f,
col->a / 255.f
);
}
} // graphics
} // jin
#endif // JIN_MODULES_RENDER
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