From 747b4d1e8633c07cdd3a16c4dbf7167df9dc5ab5 Mon Sep 17 00:00:00 2001
From: Mylloon <kennel.anri@tutanota.com>
Date: Mon, 1 May 2023 01:00:50 +0200
Subject: [PATCH] basic light

---
 main.c            | 60 +++++++++++++++++++++++++++++++++++++++++++++--
 shaders/lights.fs | 22 +++++++++++++++++
 shaders/lights.vs | 17 ++++++++++++++
 3 files changed, 97 insertions(+), 2 deletions(-)
 create mode 100644 shaders/lights.fs
 create mode 100644 shaders/lights.vs

diff --git a/main.c b/main.c
index c94b212..19412fd 100644
--- a/main.c
+++ b/main.c
@@ -2,10 +2,13 @@
 #include <stdio.h>
 
 static void init(void);
+static void resize(int, int);
 static void draw(void);
 static void sortie(void);
 
 static GLuint _wW = 1280, _wH = 720;
+static GLuint _quadId = 0;
+static GLuint _pId = 0;
 
 int main(int argc, char **argv) {
   if (!gl4duwCreateWindow(argc, argv, "Demo API8 2023", GL4DW_POS_CENTERED,
@@ -17,14 +20,67 @@ int main(int argc, char **argv) {
 
   init();
   atexit(sortie);
+  gl4duwResizeFunc(resize);
   gl4duwDisplayFunc(draw);
   gl4duwMainLoop();
 
   return 0;
 }
 
-void init(void) {}
+void init(void) {
+  glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
+  _quadId = gl4dgGenQuadf();
+  _pId = gl4duCreateProgram("<vs>shaders/lights.vs", "<fs>shaders/lights.fs",
+                            NULL);
+  glEnable(GL_DEPTH_TEST);
+  gl4duGenMatrix(GL_FLOAT, "proj");
+  gl4duGenMatrix(GL_FLOAT, "mod");
+  gl4duGenMatrix(GL_FLOAT, "view");
+  resize(_wW, _wH);
+}
 
-void draw(void) {}
+static void resize(int width, int height) {
+  GLfloat ratio;
+  _wW = width;
+  _wH = height;
+  glViewport(0, 0, _wW, _wH);
+  ratio = (GLfloat)_wW / (GLfloat)_wH;
+  gl4duBindMatrix("proj");
+  gl4duLoadIdentityf();
+  gl4duFrustumf(-1 * ratio, 1 * ratio, -1, 1, 2, 100);
+}
+
+void draw(void) {
+  glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
+
+  // Vue
+  gl4duBindMatrix("view");
+  gl4duLoadIdentityf();
+  gl4duLookAtf(0, 0, 4.f, 0, 0, 0, 0.f, 1.f, 0);
+
+  // Scene
+  // clang-format off
+  GLfloat rouge[]   = {1.f, 0.f,  0.f, 1.f},
+          blanc[]   = {1.f, 1.f,  1.f, 1.f},
+          lumpos0[] = {0.f, 0.f, 1.1f, 1.f},
+          lumpos[4],
+          *mat;
+  // clang-format on
+
+  static GLdouble x = 0.;
+  lumpos0[0] = 4.f * (float)sin(x);
+  gl4duBindMatrix("view");
+  mat = (GLfloat *)gl4duGetMatrixData();
+  MMAT4XVEC4(lumpos, mat, lumpos0);
+  gl4duBindMatrix("mod");
+  gl4duLoadIdentityf();
+  glUseProgram(_pId);
+  gl4duSendMatrices();
+  glUniform4fv(glGetUniformLocation(_pId, "scolor"), 1, rouge);
+  glUniform4fv(glGetUniformLocation(_pId, "lcolor"), 1, blanc);
+  glUniform4fv(glGetUniformLocation(_pId, "lumpos"), 1, lumpos);
+  gl4dgDraw(_quadId);
+  glUseProgram(0);
+}
 
 void sortie(void) { gl4duClean(GL4DU_ALL); }
diff --git a/shaders/lights.fs b/shaders/lights.fs
new file mode 100644
index 0000000..9fee1c8
--- /dev/null
+++ b/shaders/lights.fs
@@ -0,0 +1,22 @@
+#version 330
+
+in vec4 mvpos;
+in vec3 N;
+
+out vec4 fragColor;
+
+uniform vec4 scolor;
+uniform vec4 lcolor;
+uniform vec4 lumpos;
+
+void main() {
+  vec4 ambient = 0.15f * lcolor * scolor;
+  vec3 Ld = normalize(mvpos.xyz - lumpos.xyz);
+  float ild = clamp(dot(normalize(N), -normalize(Ld)), 0, 1);
+  vec4 diffus = (ild * lcolor) * scolor;
+  vec3 R = reflect(Ld, N);
+  vec3 Vue = vec3(0, 0, -1);
+  float ils = pow(clamp(dot(R, -Vue), 0, 1), 10);
+  vec4 spec = ils * lcolor;
+  fragColor = ambient + diffus + spec;
+}
diff --git a/shaders/lights.vs b/shaders/lights.vs
new file mode 100644
index 0000000..a2e10de
--- /dev/null
+++ b/shaders/lights.vs
@@ -0,0 +1,17 @@
+#version 330
+
+layout(location = 0) in vec3 pos;
+layout(location = 1) in vec3 normal;
+
+uniform mat4 proj;
+uniform mat4 mod;
+uniform mat4 view;
+
+out vec4 mvpos;
+out vec3 N;
+
+void main() {
+  N = (inverse(transpose(mod)) * vec4(normal, 0)).xyz;
+  mvpos = view * mod * vec4(pos, 1.0);
+  gl_Position = proj * mvpos;
+}