I just got DMD2 Derelict3 (SDL2/GL3/SDL2Image) up and running.
Since there is not much by way of documentation or running code
floating about I thought I'd drop what worked for me here. The
code is a basic c style main and functions. The code contains a
cool snip of code for flipping images to get them proper with
openGL by tito
http://stackoverflow.com/questions/5862097/sdl-opengl-screenshot-is-black.
First a brief rundown of what I found to be required and where (I
am using XP):
1) a built version of Derelict3 with sc.ini properly configured
(http://www.sjonesart.com/gl.php) I have a link showing how to
set up DMD2 Eclipse and Derelict.
2) driver files SDL2.dll and SDL2_Image.dll both of which
aldacron has provided as binaries
https://github.com/aldacron/Derelict3/downloads. These files need
to be placed in the same folder as your compiled .exe
3) I also required libpng15-15.dll and zlib1.dll be placed
alongside the SDL2 dlls.
//THE CODE~~
import std.stdio;
import std.string;
import std.conv;
import std.path;
import std.file;
import derelict.sdl2.sdl;
import derelict.sdl2.image;
import derelict.opengl3.gl3;
pragma(lib, "DerelictUtil.lib");
pragma(lib, "DerelictSDL2.lib");
pragma(lib, "DerelictGL3.lib");
SDL_Window *win;
SDL_GLContext context;
int w=800, h=600;
bool running=true;
uint shader = 0, vao = 0, tid = 0, colLoc = 0;
int flags=SDL_WINDOW_OPENGL | SDL_WINDOW_BORDERLESS |
SDL_WINDOW_SHOWN;
bool initSDL_GL(){
if(SDL_Init(SDL_INIT_VIDEO) < 0){
writefln("Error initializing SDL");
return false;
}
SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION, 3);
SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION, 2);
SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER, 1);
SDL_GL_SetAttribute(SDL_GL_DEPTH_SIZE, 24);
win=SDL_CreateWindow("3Doodle", SDL_WINDOWPOS_CENTERED,
SDL_WINDOWPOS_CENTERED, w, h, flags);
if(!win){
writefln("Error creating SDL window");
SDL_Quit();
return false;
}
context=SDL_GL_CreateContext(win);
SDL_GL_SetSwapInterval(1);
glClearColor(0.0, 0.0, 0.0, 1.0);
glViewport(0, 0, w, h);
DerelictGL3.reload();
return true;
}
bool initShaders(){
const string vshader="
#version 330
layout(location = 0) in vec3 pos;
layout(location = 1) in vec2 texCoords;
out vec2 coords;
void main(void)
{
coords=texCoords.st;
gl_Position = vec4(pos, 1.0);
}
";
const string fshader="
#version 330
uniform sampler2D colMap;
in vec2 coords;
void main(void)
{
vec3 col=texture2D(colMap, coords.st).xyz;
gl_FragColor = vec4(col, 1.0);
}
";
shader=glCreateProgram();
if(shader == 0){
writeln("Error: GL did not assigh main shader program id");
return false;
}
int vshad=glCreateShader(GL_VERTEX_SHADER);
const char *vptr=toStringz(vshader);
glShaderSource(vshad, 1, &vptr, null);
glCompileShader(vshad);
int status, len;
glGetShaderiv(vshad, GL_COMPILE_STATUS, &status);
if(status==GL_FALSE){
glGetShaderiv(vshad, GL_INFO_LOG_LENGTH, &len);
char[] error=new char[len];
glGetShaderInfoLog(vshad, len, null, cast(char*)error);
writeln(error);
return false;
}
int fshad=glCreateShader(GL_FRAGMENT_SHADER);
const char *fptr=toStringz(fshader);
glShaderSource(fshad, 1, &fptr, null);
glCompileShader(fshad);
glGetShaderiv(vshad, GL_COMPILE_STATUS, &status);
if(status==GL_FALSE){
glGetShaderiv(fshad, GL_INFO_LOG_LENGTH, &len);
char[] error=new char[len];
glGetShaderInfoLog(fshad, len, null, cast(char*)error);
writeln(error);
return false;
}
glAttachShader(shader, vshad);
glAttachShader(shader, fshad);
glLinkProgram(shader);
glGetShaderiv(shader, GL_LINK_STATUS, &status);
if(status==GL_FALSE){
glGetShaderiv(shader, GL_INFO_LOG_LENGTH, &len);
char[] error=new char[len];
glGetShaderInfoLog(shader, len, null, cast(char*)error);
writeln(error);
return false;
}
return true;
}
bool initVAO(){
uint vbov, vboc;
const float[] v = [ -0.75f, -0.75f, 0.0f,
0.75f, 0.75f, 0.0f,
-0.75f, 0.75f, 0.0f];
const float[] c = [ 0.0f, 0.0f,
1.0f, 1.0f,
0.0f, 1.0f];
glGenVertexArrays(1, &vao);
assert(vao > 0);
glBindVertexArray(vao);
glGenBuffers(1, &vbov);
assert(vbov > 0);
glBindBuffer(GL_ARRAY_BUFFER, vbov);
glBufferData(GL_ARRAY_BUFFER, v.length * GL_FLOAT.sizeof, v.ptr,
GL_STATIC_DRAW);
glEnableVertexAttribArray(0);
glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 0, null);
glBindBuffer(GL_ARRAY_BUFFER, 0);
glGenBuffers(1, &vboc);
assert(vboc > 0);
glBindBuffer(GL_ARRAY_BUFFER, vboc);
glBufferData(GL_ARRAY_BUFFER, c.length * GL_FLOAT.sizeof, c.ptr,
GL_STATIC_DRAW);
glEnableVertexAttribArray(1);
glVertexAttribPointer(1, 2, GL_FLOAT, GL_FALSE, 0, null);
glBindBuffer(GL_ARRAY_BUFFER, 0);
glBindVertexArray(0);
return true;
}
bool initUniforms(){
colLoc=glGetUniformLocation(shader, "colMap");
if(colLoc == -1){writeln("Error: main shader did not assign id
to sampler2D colMap"); return false;}
glUseProgram(shader);
glUniform1i(colLoc, 0);
glUseProgram(0);
return true;
}
bool initTex(){
assert(exists("MaoriPartyTransforms.png"));
SDL_Surface *s=IMG_Load("MaoriPartyTransforms.png");
assert(s);
glPixelStorei(GL_UNPACK_ALIGNMENT, 4);
glGenTextures(1, &tid);
assert(tid > 0);
glBindTexture(GL_TEXTURE_2D, tid);
int mode = GL_RGB;
if(s.format.BytesPerPixel == 4) mode=GL_RGBA;
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER,
GL_LINEAR);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
glTexImage2D(GL_TEXTURE_2D, 0, mode, s.w, s.h, 0, mode,
GL_UNSIGNED_BYTE, flip(s).pixels);
SDL_FreeSurface(s);
return true;
}
//thanks to tito
http://stackoverflow.com/questions/5862097/sdl-opengl-screenshot-is-black
SDL_Surface* flip(SDL_Surface* sfc)
{
SDL_Surface* result = SDL_CreateRGBSurface(sfc.flags, sfc.w,
sfc.h,
sfc.format.BytesPerPixel * 8, sfc.format.Rmask,
sfc.format.Gmask,
sfc.format.Bmask, sfc.format.Amask);
ubyte* pixels = cast(ubyte*) sfc.pixels;
ubyte* rpixels = cast(ubyte*) result.pixels;
uint pitch = sfc.pitch;
uint pxlength = pitch*sfc.h;
assert(result != null);
for(uint line = 0; line < sfc.h; ++line) {
uint pos = line * pitch;
rpixels[pos..pos+pitch] =
pixels[(pxlength-pos)-pitch..pxlength-pos];
}
return result;
}
int main(){
try{
DerelictSDL2.load();
}catch(Exception e){
writeln("Error loading SDL2 lib");
return false;
}
try{
DerelictGL3.load();
}catch(Exception e){
writeln("Error loading GL3 lib");
return false;
}
try{
DerelictSDL2Image.load();
}catch(Exception e){
writeln("Error loading SDL image lib ", e);
return false;
}
writeln("Init SDL_GL: ", initSDL_GL());
writeln("Init shaders: ", initShaders());
writeln("Init VAO: ", initVAO());
writeln("Init uniforms: ", initUniforms());
writeln("Init textures: ", initTex());
while(running){
SDL_Event e;
while(SDL_PollEvent(&e)){
switch(e.type){
case SDL_KEYDOWN:
running=false;
break;
default:
break;
}
}
glClear(GL_COLOR_BUFFER_BIT);
glUseProgram(shader);
glBindVertexArray(vao);
glActiveTexture(GL_TEXTURE0);
glBindTexture(GL_TEXTURE_2D, tid);
glDrawArrays(GL_TRIANGLES, 0, 6);
glBindTexture(GL_TEXTURE_2D, 0);
glBindVertexArray(0);
glUseProgram(0);
SDL_GL_SwapWindow(win);
}
SDL_GL_DeleteContext(context);
SDL_DestroyWindow(win);
SDL_Quit();
return 0;
}
