#include <stdio.h>
#include <string.h>
#include <stdlib.h>

#ifdef _arch_dreamcast
#include <kos.h>
#endif

#include "GL/gl.h"
#include "GL/glu.h"
#include "GL/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
    glEnable(GL_TEXTURE_2D);
    glDisable(GL_CULL_FACE);

    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();				// Reset The Projection Matrix

    gluPerspective(45.0f,(GLfloat)Width/(GLfloat)Height,0.1f,100.0f);	// Calculate The Aspect Ratio Of The Window

    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);
}

int check_start() {
#ifdef _arch_dreamcast
    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)
            return state->buttons & CONT_START;
    }
#endif

    return 0;
}

static GLfloat movement = -10.0f;
static GLfloat rotation = 0.0f;

void update_movement() {
#ifdef _arch_dreamcast
    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(state->buttons & CONT_DPAD_UP) {
                movement += 0.5f;
            } else if(state->buttons & CONT_DPAD_DOWN) {
                movement -= 0.5f;
            }

            if(state->buttons & CONT_DPAD_LEFT) {
                rotation += 0.5f;
            } else if(state->buttons & CONT_DPAD_RIGHT) {
                rotation -= 0.5f;
            }
        }
    }
#endif
}

/* 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

    glPushMatrix();
        glTranslatef(0.0f, -1.0f, movement);
        glRotatef(rotation, 0.0f, 1.0, 0.0f);

        /* We create a horseshoe shape tri-strip here because that allows for situations where a strip
           leaves and re-enters the viewport */

        glBegin(GL_TRIANGLE_STRIP);
            // Left side
            glColor3f(1.0f, 1.0f, 0.0f);
            glVertex3f(-2.0f, 0.0f, 5.0f);

            glColor3f(1.0f, 1.0f, 0.0f);
            glVertex3f(-1.0f, 0.0f, 5.0f);

            glColor3f(1.0f, 1.0f, 0.0f);
            glVertex3f(-2.0f, 0.0f, 3.0f);

            glColor3f(1.0f, 1.0f, 0.0f);
            glVertex3f(-1.0f, 0.0f, 3.0f);

            glColor3f(1.0f, 1.0f, 0.0f);
            glVertex3f(-2.0f, 0.0f, 1.0f);

            glColor3f(1.0f, 1.0f, 0.0f);
            glVertex3f(-1.0f, 0.0f, 1.0f);

            // Curve
            glColor3f(0.0f, 1.0f, 0.0f);
            glVertex3f(-1.0f, 0.0f, -1.0f);

            glColor3f(0.0f, 1.0f, 0.0f);
            glVertex3f(1.0f, 0.0f, 1.0f);

            glColor3f(0.0f, 1.0f, 0.0f);
            glVertex3f(1.0f, 0.0f, -1.0f);

            // Right side
            // Degenerate to reverse ordering
            glColor3f(1.0f, 0.0f, 0.0f);
            glVertex3f(2.0f, 0.0f, 1.0f);

            glColor3f(0.0f, 1.0f, 0.0f);
            glVertex3f(1.0f, 0.0f, 1.0f);

            glColor3f(1.0f, 0.0f, 0.0f);
            glVertex3f(1.0f, 0.0f, 3.0f);

            glColor3f(1.0f, 0.0f, 0.0f);
            glVertex3f(2.0f, 0.0f, 3.0f);

            glColor3f(1.0f, 0.0f, 0.0f);
            glVertex3f(1.0f, 0.0f, 5.0f);

            glColor3f(1.0f, 0.0f, 0.0f);
            glVertex3f(2.0f, 0.0f, 5.0f);
        glEnd();
    glPopMatrix();

    // 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) {
        if(check_start())
            break;

        update_movement();

        DrawGLScene();
    }

    return 0;
}