[examples] Added shaders_color_correction (#5307)

* [examples] Added `shaders_color_correction`

* Add _CRT_SECURE_NO_WARNINGS to VS Project

* Added to makefiles

examples/shaders/resources/shaders/glsl100/color_correction.fs

@@ -0,0 +1,34 @@
+#version 100
+
+precision mediump float;
+
+// Input vertex attributes (from vertex shader)
+varying vec2 fragTexCoord;
+varying vec4 fragColor;
+
+// Input uniform values
+uniform sampler2D texture0;
+uniform vec4 colDiffuse;
+
+uniform float contrast;
+uniform float saturation;
+uniform float brightness;
+
+void main()
+{
+    // Get texel color
+    vec4 texel = texture2D(texture0, fragTexCoord);
+
+    // Apply contrast
+    texel.rgb = (texel.rgb - 0.5)*(contrast/100.0 + 1.0) + 0.5;
+
+    // Apply brightness
+    texel.rgb = texel.rgb + brightness/100.0;
+
+    // Apply saturation
+    float intensity = dot(texel.rgb, vec3(0.299, 0.587, 0.114));
+    texel.rgb = (texel.rgb - intensity)*saturation/100.0 + texel.rgb;
+
+    // Output resulting color
+    gl_FragColor = texel;
+}

examples/shaders/resources/shaders/glsl120/color_correction.fs

@@ -0,0 +1,31 @@
+#version 120
+
+// Input vertex attributes (from vertex shader)
+varying vec2 fragTexCoord;
+varying vec4 fragColor;
+
+// Input uniform values
+uniform sampler2D texture0;
+uniform vec4 colDiffuse;
+
+uniform float contrast;
+uniform float saturation;
+uniform float brightness;
+
+void main()
+{
+    vec4 texel = texture2D(texture0, fragTexCoord);   // Get texel color
+
+    // Apply contrast
+    texel.rgb = (texel.rgb - 0.5)*(contrast/100.0 + 1.0) + 0.5;
+
+    // Apply brightness
+    texel.rgb = texel.rgb + brightness/100.0;
+
+    // Apply saturation
+    float intensity = dot(texel.rgb, vec3(0.299, 0.587, 0.114));
+    texel.rgb = (texel.rgb - intensity)*saturation/100.0 + texel.rgb;
+
+    // Output resulting color
+    gl_FragColor = texel;
+}

examples/shaders/resources/shaders/glsl330/color_correction.fs

@@ -0,0 +1,34 @@
+#version 330
+
+// Input vertex attributes (from vertex shader)
+in vec2 fragTexCoord;
+in vec4 fragColor;
+
+// Input uniform values
+uniform sampler2D texture0;
+uniform vec4 colDiffuse;
+
+uniform float contrast;
+uniform float saturation;
+uniform float brightness;
+
+// Output fragment color
+out vec4 finalColor;
+
+void main()
+{
+    vec4 texel = texture(texture0, fragTexCoord);   // Get texel color
+
+    // Apply contrast
+    texel.rgb = (texel.rgb - 0.5f)*(contrast/100.0f + 1.0f) + 0.5f;
+
+    // Apply brightness
+    texel.rgb = texel.rgb + brightness/100.0f;
+
+    // Apply saturation
+    float intensity = dot(texel.rgb, vec3(0.299f, 0.587f, 0.114f));
+    texel.rgb = (texel.rgb - intensity)*saturation/100.0f + texel.rgb;
+
+    // Output resulting color
+    finalColor = texel;
+}