Trying to make paint pallet like tutorial and editing it
i keep getting unresolved external symbol _main referenced in function "int __cdecl invoke_main(void)" (?invoke_main
and error with `selectedColour;` it should containt the selected color from the array of struct colour
#include <GL\glew.h>
#include <GL\freeglut.h>
class ColourPalette {
struct Colour {
float r, g, b;
};
public:
// Array of colours in the palette
static const Colour colours[];
static const Colour selectedColour;
// index of selected colour in above array
static int selectedIndex;
// x position of the palette, based on window width
static int palette_x_pos;
/*
Draws the colour palette on the screen
This is called from inside the "display" function
@param window_width - Width of the window
@param window_height - Height of the window
*/
static void Display(int window_width, int window_height) {
palette_x_pos = window_width - 50;
// draw the button for each colour (these are not from the Button class! they are implemented here)
glBegin(GL_QUADS);
int xPos = palette_x_pos;
int yPos = 50;
for (int i = 0; i < 5; i++) {
// Draw border for the colour
// different coloured border depending on whether it is selected or not
if (i == selectedIndex) {
glColor3f(0.6f, 0.6f, 0.6f);
}
else {
glColor3f(0.2f, 0.2f, 0.2f);
}
glVertex2f(xPos, window_height - yPos);
glVertex2f(xPos + 50, window_height - yPos);
glVertex2f(xPos + 50, window_height - (yPos + 50));
glVertex2f(xPos, window_height - (yPos + 50));
// Now draw the colour box itself
glColor3f(colours[i].r, colours[i].g, colours[i].b);
glVertex2f(xPos + 2, window_height - (yPos + 2));
glVertex2f(xPos + 46, window_height - (yPos + 2));
glVertex2f(xPos + 46, window_height - (yPos + 46));
glVertex2f(xPos + 2, window_height - (yPos + 46));
yPos += 49;
}
glEnd();
}
/*
Checks if (x,y) coordinate is within a given rect
@param x - x coordinate of point to test
@param y - y coordinate of point to test
@param x_pos - x coordinate of the rect (top left)
@param y_pos - y coordinate of the rect (top left)
@param width - width of the rect
@param height - height of the rect
@return True if the point lies within the rect
*/
static bool checkInside(int x, int y, int x_pos, int y_pos, int width, int height) {
if (x >= x_pos) {
if (y >= y_pos) {
if (x < x_pos + width) {
if (y < y_pos + height) {
return true;
}
}
}
}
return false;
}
/*
Handles mouse pressed events for the colour palette
@param button - Mouse button pressed
@param state - State of mouse event (down or up)
@param x - The x coordinate of the mouse when pressed
@param y - The y coordinate of the mouse when pressed
@return Has the colour palette handled the event?
*/
static bool Pressed(int button, int state, int x, int y) {
if (button == GLUT_LEFT_BUTTON) {
if (state == GLUT_UP) {
int xPos = palette_x_pos;
int yPos = 50;
for (int i = 0; i < 5; i++) {
// Check if the mouse is inside each colour rect
if (checkInside(x, y, xPos, yPos, 50, 50)) {
// select the colour
selectedIndex = i;
selectedColour = colours[i];
return true;
}
yPos += 49;
}
}
}
// block the event from continuing if the mouse is over the colour palette
return checkInside(x, y, palette_x_pos, 50, 50, 245);
}
};
