feat: add polygon_offset sample

samples/polygon_offset/Makefile

@@ -0,0 +1,23 @@
+TARGET = offset.elf
+OBJS = main.o
+
+all: rm-elf $(TARGET)
+
+include $(KOS_BASE)/Makefile.rules
+
+clean:
+	-rm -f $(TARGET) $(OBJS)
+
+rm-elf:
+	-rm -f $(TARGET)
+
+$(TARGET): $(OBJS) 
+	$(KOS_CC) $(KOS_CFLAGS) $(KOS_LDFLAGS) -o $(TARGET) $(KOS_START) \
+		$(OBJS) $(OBJEXTRA) -lm -lkosutils $(KOS_LIBS)
+
+run: $(TARGET)
+	$(KOS_LOADER) $(TARGET)
+
+dist: $(TARGET)
+	$(KOS_CC_BASE)/sh-elf/bin/objcopy -R .stack -O binary $(TARGET) $(basename $(TARGET))
+	$(KOS_BASE)/utils/scramble/scramble $(basename $(TARGET)) 1ST_READ.BIN

samples/polygon_offset/main.c

@@ -0,0 +1,215 @@
+#include <kos.h>
+typedef enum
+{
+    false,
+    true
+} bool;
+#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(0.93f, 0.93f, 0.93f, 0.0f);
+    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
+
+    gluPerspective(45.0f, (GLfloat)Width / (GLfloat)Height, 1.0f, 100.0f); // Calculate The Aspect Ratio Of The Window
+
+    glMatrixMode(GL_MODELVIEW);
+}
+
+/* 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, 1.0f, 100.0f);
+    glMatrixMode(GL_MODELVIEW);
+}
+
+float xrot = 0.0f;
+float yrot = 0.0f;
+
+float xdiff = 0;
+float ydiff = 0;
+
+bool offset = true;
+
+void drawBox()
+{
+    glBegin(GL_QUADS);
+    // FRONT
+    glVertex3f(-0.5f, -0.5f, 0.5f);
+    glVertex3f(0.5f, -0.5f, 0.5f);
+    glVertex3f(0.5f, 0.5f, 0.5f);
+    glVertex3f(-0.5f, 0.5f, 0.5f);
+    // BACK
+    glVertex3f(-0.5f, -0.5f, -0.5f);
+    glVertex3f(-0.5f, 0.5f, -0.5f);
+    glVertex3f(0.5f, 0.5f, -0.5f);
+    glVertex3f(0.5f, -0.5f, -0.5f);
+    // LEFT
+    glVertex3f(-0.5f, -0.5f, 0.5f);
+    glVertex3f(-0.5f, 0.5f, 0.5f);
+    glVertex3f(-0.5f, 0.5f, -0.5f);
+    glVertex3f(-0.5f, -0.5f, -0.5f);
+    // RIGHT
+    glVertex3f(0.5f, -0.5f, -0.5f);
+    glVertex3f(0.5f, 0.5f, -0.5f);
+    glVertex3f(0.5f, 0.5f, 0.5f);
+    glVertex3f(0.5f, -0.5f, 0.5f);
+    // TOP
+    glVertex3f(-0.5f, 0.5f, 0.5f);
+    glVertex3f(0.5f, 0.5f, 0.5f);
+    glVertex3f(0.5f, 0.5f, -0.5f);
+    glVertex3f(-0.5f, 0.5f, -0.5f);
+    // BOTTOM
+    glVertex3f(-0.5f, -0.5f, 0.5f);
+    glVertex3f(-0.5f, -0.5f, -0.5f);
+    glVertex3f(0.5f, -0.5f, -0.5f);
+    glVertex3f(0.5f, -0.5f, 0.5f);
+    glEnd();
+}
+
+void drawPolygon()
+{
+    glBegin(GL_QUADS);
+    glVertex3f(-0.5f, -0.5f, 0.0f);
+    glVertex3f(0.5f, -0.5f, 0.0f);
+    glVertex3f(0.5f, 0.5f, 0.0f);
+    glVertex3f(-0.5f, 0.5f, 0.0f);
+    glEnd();
+}
+int frames = 0;
+void check_input()
+{
+    maple_device_t *cont;
+    cont_state_t *state;
+
+    cont = maple_enum_type(0, MAPLE_FUNC_CONTROLLER);
+
+    if (cont)
+    {
+        state = (cont_state_t *)maple_dev_status(cont);
+
+        if (state)
+        {
+            if (frames <= 0)
+            {
+                if (state->buttons & CONT_START)
+                {
+                    offset = !offset;
+                    frames = 60;
+                }
+            }
+        }
+    }
+}
+
+/* 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
+
+    gluLookAt(
+        0.0f, 0.0f, 3.0f,
+        0.0f, 0.0f, 0.0f,
+        0.0f, 1.0f, 0.0f);
+
+    glRotatef(xrot, 1.0f, 0.0f, 0.0f);
+    glRotatef(yrot, 0.0f, 1.0f, 0.0f);
+
+    //glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
+
+    glColor3f(1.0f, 0.0f, 0.0f);
+    //glPolygonMode(GL_FRONT_AND_BACK, GL_FILL);
+    drawBox();
+
+    if (offset)
+    {
+        glEnable(GL_POLYGON_OFFSET_FILL);
+        glPolygonOffset(1.0f, 1.0f);
+    }
+
+    glColor3f(0.0f, 1.0f, 0.0f);
+    glPushMatrix();
+    glTranslatef(-0.25f, -0.25f, 0.5f);
+    glScalef(0.5f, 0.5f, 0.5f);
+    drawPolygon();
+    glPopMatrix();
+
+    glColor3f(1.0f, 1.0f, 0.0f);
+    glPushMatrix();
+    glTranslatef(0.25f, 0.25f, 0.5f);
+    glScalef(0.5f, 0.5f, 0.5f);
+    drawPolygon();
+    glPopMatrix();
+
+    if (offset)
+    {
+        glEnable(GL_POLYGON_OFFSET_FILL);
+        glPolygonOffset(-1.0f, -1.0f);
+    }
+
+    glColor3f(0.0f, 0.0f, 1.0f);
+    glPushMatrix();
+    glTranslatef(0.0f, 0.0f, 0.5f);
+    glScalef(0.5f, 0.5f, 0.5f);
+    drawPolygon();
+    glPopMatrix();
+
+    if (offset)
+        glDisable(GL_POLYGON_OFFSET_FILL);
+#if 0
+    if (offset)
+    {
+        glEnable(GL_POLYGON_OFFSET_LINE);
+        glPolygonOffset(-1.0f, -1.0f);
+    }
+
+
+	glColor3f(0.0f, 0.0f, 0.0f);
+	glPolygonMode(GL_FRONT_AND_BACK, GL_LINE);
+	drawBox();
+
+	if (offset)
+		glDisable(GL_POLYGON_OFFSET_LINE);
+
+	glFlush();
+#endif
+    // 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)
+    {
+        check_input();
+        DrawGLScene();
+        xrot += 0.1f;
+        yrot += 0.25f;
+        frames--;
+    }
+
+    return 0;
+}