Merge branch 'master' into 'master'

SAMPLE : depth testing with ortho projection

See merge request simulant/GLdc!59

samples/depth_funcs_ortho/Makefile

@@ -0,0 +1,29 @@
+TARGET = depth_funcs.elf
+OBJS = main.o
+
+all: rm-elf $(TARGET)
+
+include $(KOS_BASE)/Makefile.rules
+
+clean:
+	-rm -f $(TARGET) $(OBJS) romdisk.*
+
+rm-elf:
+	-rm -f $(TARGET) romdisk.*
+
+$(TARGET): $(OBJS) romdisk.o
+	$(KOS_CC) $(KOS_CFLAGS) $(KOS_LDFLAGS) -o $(TARGET) $(KOS_START) \
+		$(OBJS) romdisk.o $(OBJEXTRA) -lm -lkosutils $(KOS_LIBS)
+
+romdisk.img:
+	$(KOS_GENROMFS) -f romdisk.img -d romdisk -v
+
+romdisk.o: romdisk.img
+	$(KOS_BASE)/utils/bin2o/bin2o romdisk.img romdisk romdisk.o
+
+run: $(TARGET)
+	$(KOS_LOADER) $(TARGET)
+
+dist:
+	rm -f $(OBJS) romdisk.o romdisk.img
+	$(KOS_STRIP) $(TARGET)

samples/depth_funcs_ortho/main.c

@@ -0,0 +1,83 @@
+#include "gl.h"
+#include "glu.h"
+#include "glkos.h"
+
+/* A general OpenGL initialization function.  Sets all of the initial parameters. */
+void InitGL(int Width, int Height)	        // We call this right after our OpenGL window is created.
+{
+    glClearColor(0.0f, 0.0f, 0.0f, 0.0f);		// This Will Clear The Background Color To Black
+    glClearDepth(1.0);				// Enables Clearing Of The Depth Buffer
+    glDepthFunc(GL_LEQUAL);				// The Type Of Depth Test To Do
+    glEnable(GL_DEPTH_TEST);			// Enables Depth Testing
+    glShadeModel(GL_SMOOTH);			// Enables Smooth Color Shading
+
+    glMatrixMode(GL_PROJECTION);
+    glLoadIdentity();				// Reset The Projection Matrix
+    glOrtho(0.0, 640.0, 0.0, 480.0, 0.0, 1.0);
+
+    glMatrixMode(GL_MODELVIEW);
+    glLoadIdentity();
+}
+
+/* The function called when our window is resized (which shouldn't happen, because we're fullscreen) */
+void ReSizeGLScene(int Width, int Height)
+{
+    if (Height == 0)				// Prevent A Divide By Zero If The Window Is Too Small
+        Height = 1;
+
+    glViewport(0, 0, Width, Height);		// Reset The Current Viewport And Perspective Transformation
+
+    glMatrixMode(GL_PROJECTION);
+    glLoadIdentity();
+
+    //gluPerspective(45.0f,(GLfloat)Width/(GLfloat)Height,0.1f,100.0f);
+    glMatrixMode(GL_MODELVIEW);
+}
+
+
+void DrawSquare(float width, float r, float g, float b, float z) {
+    width /= 2;
+
+    glColor3f(r, g, b);
+    glBegin(GL_QUADS);				// start drawing a polygon (4 sided)
+    glVertex3f(-width, width, z);		// Top Left
+    glVertex3f( width, width, z);		// Top Right
+    glVertex3f( width,-width, z);		// Bottom Right
+    glVertex3f(-width,-width, z);		// Bottom Left
+    glEnd();					// done with the polygon
+}
+
+/* The main drawing function. */
+void DrawGLScene()
+{
+    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);		// Clear The Screen And The Depth Buffer
+    glLoadIdentity();				// Reset The View
+
+    // Center fo the screen.
+    glTranslatef(320, 240, 0);
+
+    glDepthFunc(GL_LEQUAL);
+    //RED over GREEN over BLUE
+    DrawSquare(100.0, 1.0, 0.0, 0.0, 0.0);
+    glTranslatef(50, 0, 0.03f);
+    DrawSquare(100, 0, 1, 0, 0);
+    glTranslatef(50, 0, 0.03f);
+    DrawSquare(100, 0, 0, 1, 0);
+
+    // swap buffers to display, since we're double buffered.
+    glKosSwapBuffers();
+}
+
+int main(int argc, char **argv)
+{
+    glKosInit();
+
+    InitGL(640, 480);
+    ReSizeGLScene(640, 480);
+
+    while(1) {
+        DrawGLScene();
+    }
+
+    return 0;
+}