draw a triangle

i wonder where kitty-cricket learnt this one from

1 files changed, 45 insertions, 5 deletions

diff --git a/graph.c b/graph.c
index 1063a50..fba4106 100644
--- a/graph.c
+++ b/graph.c
@@ -6,20 +6,22 @@
 #include"graph.h"
 
 _ SDL_Window*win;
-_ SDL_GLContext ctx;
 _ U32 win_w=1280;
 _ U32 win_h=720;
+_ SDL_GLContext ctx;
+
 _ V on_err(IM C*d){die("Could not %s: %s\n",d,SDL_GetError());}
 
 V graph_init(V){SDL_version sdl_vh,sdl_vl;
   Q(SDL_Init(SDL_INIT_VIDEO),on_err("init sdl2"))
   SDL_GL_SetAttribute(SDL_GL_CONTEXT_MAJOR_VERSION,3),
   SDL_GL_SetAttribute(SDL_GL_CONTEXT_MINOR_VERSION,3),
-  SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK,SDL_GL_CONTEXT_PROFILE_CORE);
-  N(win=SDL_CreateWindow("mino",SDL_WINDOWPOS_CENTERED,SDL_WINDOWPOS_CENTERED,win_w,win_h,SDL_WINDOW_RESIZABLE|SDL_WINDOW_OPENGL),on_err("create window"))
+  SDL_GL_SetAttribute(SDL_GL_CONTEXT_PROFILE_MASK,SDL_GL_CONTEXT_PROFILE_CORE),
+  SDL_GL_SetAttribute(SDL_GL_DOUBLEBUFFER,1);
+  N(win=SDL_CreateWindow("mino",SDL_WINDOWPOS_CENTERED,SDL_WINDOWPOS_CENTERED,win_w,win_h,SDL_WINDOW_OPENGL),on_err("create window"))
   N(ctx=SDL_GL_CreateContext(win),on_err("create OpenGL context"))
-  N(gladLoadGLLoader((GLADloadproc)SDL_GL_GetProcAddress),on_err("load GL"))
-  SDL_GL_SetSwapInterval(-1);
+  N(gladLoadGLLoader(SDL_GL_GetProcAddress),on_err("load GL"))
+  SDL_GL_SetSwapInterval(1);
 
   SDL_VERSION(&sdl_vh)SDL_GetVersion(&sdl_vl);
   fprintf(stderr,
@@ -34,3 +36,41 @@ V graph_init(V){SDL_version sdl_vh,sdl_vl;
     glGetString(GL_VERSION),glGetString(GL_VENDOR),glGetString(GL_RENDERER));}
 
 V graph_deinit(V){SDL_GL_DeleteContext(ctx),SDL_DestroyWindow(win),SDL_Quit();}
+V graph_events(V){SDL_Event ev;WH(SDL_PollEvent(&ev),Q(SDL_QUIT==ev.type,exit(0)))}
+V graph_before(V){glClearColor(1.0,0.75,0.8,1.0),glClear(GL_COLOR_BUFFER_BIT);}
+V graph_after(V){SDL_GL_SwapWindow(win);}
+
+V graph_triangle(V){
+  IM C*vert_shader_src="#version 330 core\n"
+    "layout(location=0)in vec3 pos;void main(){gl_Position=vec4(pos.x,pos.y,pos.z,1.0);}";
+  U32 vert_shader=glCreateShader(GL_VERTEX_SHADER);
+  glShaderSource(vert_shader,1,&vert_shader_src,NULL),glCompileShader(vert_shader);
+  I success;
+  C info_log[512];
+  glGetShaderiv(vert_shader,GL_COMPILE_STATUS,&success);
+  N(success,die("error compiling vert shader"))
+
+  IM C*frag_shader_src = "#version 330 core\n"
+    "out vec4 Colour;void main(){Colour=vec4(1.0, 0.5, 0.2, 1.0);}";
+  U32 frag_shader=glCreateShader(GL_FRAGMENT_SHADER);
+  glShaderSource(frag_shader,1,&frag_shader_src,NULL),glCompileShader(frag_shader);
+  glGetShaderiv(vert_shader,GL_COMPILE_STATUS,&success);
+  N(success,die("error compiling frag shader"))
+
+  U32 shader_program=glCreateProgram();
+  glAttachShader(shader_program,vert_shader),glAttachShader(shader_program,frag_shader),
+  glLinkProgram(shader_program);//glDeleteShader(vert_shader),glDeleteShader(frag_shader);
+  glGetProgramiv(shader_program,GL_LINK_STATUS,&success);
+  N(success,glGetProgramInfoLog(shader_program,512,0,info_log),die("error linking: %s"))
+
+  IM F32 verts[]={
+    -0.5,-0.5,0.0,
+     0.5,-0.5,0.0,
+     0.0, 0.5,0.0};
+  U32 vbo,vao;
+  glGenBuffers(1,&vbo),       glBindBuffer(GL_ARRAY_BUFFER,vbo),
+  glGenVertexArrays(1,&vao),  glBindVertexArray(vao);
+  glBufferData(GL_ARRAY_BUFFER,SZ verts,verts,GL_STATIC_DRAW),
+  glVertexAttribPointer(0,3,GL_FLOAT,GL_FALSE,3*SZ verts[0],0),
+  glEnableVertexAttribArray(0),glUseProgram(shader_program),
+  glBindVertexArray(vao),glDrawArrays(GL_TRIANGLES,0,3);}