From 48c2cd638674bf8bca3276136ef8c8f826ac6e8a Mon Sep 17 00:00:00 2001
From: Robert <robert.trololo@gmail.com>
Date: Wed, 2 Sep 2020 12:32:00 +0200
Subject: [PATCH] generate random colored squares

---
 src/PlotWindow.cpp    | 14 +++++++++-----
 src/PlotWindow.hpp    |  2 +-
 src/main.cpp          |  2 ++
 src/shader/basic.frag |  5 +++--
 src/shader/basic.vert |  6 +++++-
 5 files changed, 20 insertions(+), 9 deletions(-)

diff --git a/src/PlotWindow.cpp b/src/PlotWindow.cpp
index 9799cc2..c4395c0 100644
--- a/src/PlotWindow.cpp
+++ b/src/PlotWindow.cpp
@@ -4,13 +4,15 @@
 #include <string>
 #include <fstream>
 
+#define frand() ((float)rand() / (float)RAND_MAX)
+
 PlotWindow::PlotWindow(int w, int h, int id, std::string title) :
 	window(nullptr), id(id), 
 	vertices{
-		-0.5f,  0.5f, 0.0f,
-		 0.5f,  0.5f, 0.0f,
-		 0.5f, -0.5f, 0.0f,
-		-0.5f, -0.5f, 0.0f
+		-0.5f,  0.5f, 0.0f, frand(), frand(), frand(),
+		 0.5f,  0.5f, 0.0f, frand(), frand(), frand(),
+		 0.5f, -0.5f, 0.0f, frand(), frand(), frand(),
+		-0.5f, -0.5f, 0.0f, frand(), frand(), frand()
 	}, 
 	indices{
 		0, 1, 3,
@@ -111,8 +113,10 @@ PlotWindow::PlotWindow(int w, int h, int id, std::string title) :
 	glBindBuffer(GL_ELEMENT_ARRAY_BUFFER, EBO);
 	glBufferData(GL_ELEMENT_ARRAY_BUFFER, sizeof(indices), indices, GL_STATIC_DRAW);
 
-	glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, 3 * sizeof(float), (void*)0);
+	glVertexAttribPointer(0, 3, GL_FLOAT, GL_FALSE, (3 + 3) * sizeof(float), (void*)0);
+	glVertexAttribPointer(1, 3, GL_FLOAT, GL_FALSE, (3 + 3) * sizeof(float), (void*)(3 * sizeof(float)));
 	glEnableVertexAttribArray(0);
+	glEnableVertexAttribArray(1);
 
 	glBindBuffer(GL_ARRAY_BUFFER, 0);
 	glBindVertexArray(0);
diff --git a/src/PlotWindow.hpp b/src/PlotWindow.hpp
index a837dbf..3eff205 100644
--- a/src/PlotWindow.hpp
+++ b/src/PlotWindow.hpp
@@ -34,6 +34,6 @@ private:
 	ShaderProgram shader;
 	BufferObject VAO, VBO, EBO;
 
-	float			vertices[4 * 3];
+	float			vertices[4 * 3 * 4];
 	unsigned int	indices[2 * 3];
 };
\ No newline at end of file
diff --git a/src/main.cpp b/src/main.cpp
index 8a2fff5..eaaef66 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -9,6 +9,8 @@
 
 int main(int argc, char** argv)
 {
+	srand(time(0));
+
 	int result = glfwInit();
 	if (result != GL_TRUE)
 	{
diff --git a/src/shader/basic.frag b/src/shader/basic.frag
index ba5871e..297a2b6 100644
--- a/src/shader/basic.frag
+++ b/src/shader/basic.frag
@@ -1,8 +1,9 @@
 #version 460 core
 
-out vec4 oColor;
+in vec4 vertexColor;
+out vec4 fragColor;
 
 void main()
 {
-	oColor = vec4(0.6f, 0.2f, 0.9f, 1.0f);
+	fragColor = vertexColor;
 }
diff --git a/src/shader/basic.vert b/src/shader/basic.vert
index 234598a..64efd7c 100644
--- a/src/shader/basic.vert
+++ b/src/shader/basic.vert
@@ -1,8 +1,12 @@
 #version 460 core
 
 layout (location = 0) in vec3 aPos;
+layout (location = 1) in vec3 aCol;
+
+out vec4 vertexColor;
 
 void main()
 {
-	gl_Position = vec4(aPos.x, aPos.y, aPos.z, 1.0);
+	vertexColor = vec4(aCol, 1.0f);
+	gl_Position = vec4(aPos, 1.0f);
 }