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andrea.ellinger edited this page Sep 16, 2021 · 3 revisions

This section contains all Math functions.

Table Of Contents

CP_Math_ClampInt

Clamps an int to a range and returns the clamped value. If the provided int value is less than the provided min value the min value will be returned; if the provided int value is greater than the provided max value the max value will be returned; otherwise the provided int value will be returned.

Function

int CP_Math_ClampInt(int value, int min, int max);

Parameters

  • value (int) - The value to clamp to the input range.
  • min (int) - The minimum value in the range.
  • max (int) - The maximum value in the range.

Return

  • int - The clamped value within the provided range.

Example

void update()
{
    // Get the mouse position/canvas size ratio
    float mx = (float)CP_Input_GetMouseWorldX() / (float)CP_System_GetWindowWidth();
    float my = (float)CP_Input_GetMouseWorldY() / (float)CP_System_GetWindowHeight();

    // Convert to 0-255 values for color
    int r_color = (int)(mx * 255);
    int b_color = (int)(my * 255);

    // Clamp the values
    r_color = CP_Math_ClampInt(r_color, 0, 255);
    b_color = CP_Math_ClampInt(b_color, 0, 255);

    // Set the background as the color
    CP_Graphics_ClearBackground(CP_Color_Create(r_color, 0, b_color, 255));
}

Related

CP_Math_ClampFloat

Clamps a float to a range and returns the clamped value. If the provided float value is less than the provided min value the min value will be returned; if the provided float value is greater than the provided max value the max value will be returned; otherwise the provided float value will be returned.

Function

float CP_Math_ClampFloat(float value, float min, float max);

Parameters

  • value (float) - The value to clamp to the input range.
  • min (float) - The minimum value in the range.
  • max (float) - The maximum value in the range.

Return

  • float - The clamped value within the provided range.

Example

static CP_Color Red;
static CP_Color Green;
static CP_Color Blue;
static CP_Color White;

void init()
{
    // Create colors for the four corners of the screen
    Red = CP_Color_Create(255, 0, 0, 255);
    Green = CP_Color_Create(0, 255, 0, 255);
    Blue = CP_Color_Create(0, 0, 255, 255);
    White = CP_Color_Create(255, 255, 255, 255);
}

void update()
{
    // Get the mouse position
    float mx = (float)CP_Input_GetMouseWorldX() / (float)CP_System_GetWindowWidth();
    float my = (float)CP_Input_GetMouseWorldY() / (float)CP_System_GetWindowHeight();

    // Clamp the values
    mx = CP_Math_ClampFloat(mx, 0.0, 1.0);
    my = CP_Math_ClampFloat(my, 0.0, 1.0);

    // Lerp along both axis
    CP_Color lerpx = CP_Color_Lerp(Red, Blue, mx);
    CP_Color lerpy = CP_Color_Lerp(Green, White, my);

    // Lerp them together
    CP_Color lerp = CP_Color_Lerp(lerpx, lerpy, 0.5f);

    // Set the background based on the lerp
    CP_Graphics_ClearBackground(lerp);
}

Related

CP_Math_LerpInt

Linearly interpolates between two input integers with an input lerp factor. The lerp factor should be from 0.0 to 1.0.

Function

int CP_Math_LerpInt(int a, int b, float lerpFactor);

Parameters

  • a (int) - The value the function returns when lerp_factor is 0.0, the starting value.
  • b (int) - The value the function returns when lerp_factor is 1.0, the ending value.
  • lerp_factor (float) - The ratio used to determine what value to return between a and b.

Return

  • int - The interpolated value between a and b according to lerp_factor.

Example

void update()
{
    // Get the mouse position/canvas size ratio
    float mx = (float)CP_Input_GetMouseWorldX() / (float)CP_System_GetWindowWidth();
    float my = (float)CP_Input_GetMouseWorldY() / (float)CP_System_GetWindowHeight();

    // Convert to 0-255 values for color
    int r_color = CP_Math_LerpInt(0, 255, mx);
    int b_color = CP_Math_LerpInt(0, 255, my);

    // Clamp the values
    r_color = CP_Math_ClampInt(r_color, 0, 255);
    b_color = CP_Math_ClampInt(b_color, 0, 255);

    // Set the background as the color
    CP_Graphics_ClearBackground(CP_Color_Create(r_color, 0, b_color, 255));
}

Related

CP_Math_LerpFloat

Linearly interpolates between two input floats with an input lerp factor. The lerp factor should be from 0.0 to 1.0.

Function

float CP_Math_LerpFloat(float a, float b, float lerpFactor);

Parameters

  • a (float) - The value the function returns when lerp_factor is 0.0, the starting value.
  • b (float) - The value the function returns when lerp_factor is 1.0, the ending value.
  • lerp_factor (float) - The ratio used to determine what value to return between a and b.

Return

  • float - The interpolated value between a and b according to lerp_factor.

Example

CP_Image justin_face;

void init()
{
    justin_face = CP_Image_Load("./Assets/justin1.png");
}

float rot_counter = 0;
void update()
{
    // Increment rotation lerp factor or reset
    if (rot_counter >= 1.0f)
        rot_counter -= 1.0f;
    else
        rot_counter += CP_System_GetDt();

    // Lerp rotation and draw image
    float rotation = CP_Math_LerpFloat(0.0f, 360.0f, rot_counter);
    CP_Graphics_ClearBackground(CP_Color_Create(255, 255, 255, 255));
    CP_Image_DrawAdvanced(justin_face, CP_Input_GetMouseWorldX(), CP_Input_GetMouseWorldY(), 100, 150, 255, rotation);
}

Related

CP_Math_Square

Takes in a float and returns its squared value.

Function

float CP_Math_Square(float number);

Parameters

  • number (float) - The number to square.

Return

  • float - The squared value.

Example

void square_init()
{
    CP_Settings_Fill(CP_Color_Create(0, 0, 0, 255));
    CP_Settings_TextAlignment(CP_ALIGN_H_CENTER, CP_ALIGN_V_BOTTOM);
}

float random_value = 0.0f;
float time_elapsed = 1.5;
void square_update()
{
    CP_Settings_Background(CP_Color_Create(255, 255, 255, 255));

    if (time_elapsed >= 1.5f)
    {
        random_value = CP_Random_RangeFloat(0.0f, 100.0f);
        time_elapsed = 0.0f;
    }
    else
        time_elapsed += dt();

    char num_string[128] = { 0 };
    sprintf_s(num_string, 128, "The square of %.2f is %.2f", random_value, CP_Math_Square(random_value));
    CP_Font_DrawTextBox(num_string, 0, canvasHeight / 2, canvasWidth);
}

Related

CP_Math_Distance

This function returns the distance between two provided points.

Function

float CP_Math_Distance(float x1, float y1, float x2, float y2);

Parameters

  • x1 (float) - The X coordinate of the first point.
  • y1 (float) - The Y coordinate of the first point.
  • x2 (float) - The X coordinate of the second point.
  • y2 (float) - The Y coordinate of the second point.

Return

  • float - The distance between the two provided points.

Example

float startPointX = 20.0;
float startPointY = 350.0;
float endPointX = CP_Input_GetMouseX();
float endPointY = CP_Input_GetMouseY();

float distance = CP_Math_Distance(startPointX, startPointY, endPointX, endPointY);

Related

CP_Math_Degrees

Takes an input number of radians as a float, then returns it converted to degrees as a float.

Function

float CP_Math_Degrees(float radians);

Parameters

  • radians (float) - The angle to convert to degrees from radians.

Return

  • float - The provided angle converted to degrees.

Example

void init()
{
    CP_Settings_EllipseMode(CP_POSITION_CENTER);
    CP_Font_Set(CP_Font_GetDefault(), 30);
    CP_Settings_Fill(CP_Color_Create(0, 0, 0, 255));
}

float r_radians;
float counter = 2.0f;
void update()
{
    CP_Graphics_ClearBackground(CP_Color_Create(255, 255, 255, 255));

    // Change degrees every few seconds
    if (counter >= 2.0f)
    {
        r_radians = CP_Random_RangeFloat(0.0f, PI);
        counter = 0.0f;
    }
    else
        counter += CP_System_GetDt();

    // Print out number of radians and convert to degrees
    char buffer[128] = { 0 };
    sprintf_s(buffer, 128, "Radians: %.3f\nis equal to\nDegrees: %.3f", r_radians, CP_Math_Degrees(r_radians));
    CP_Font_DrawTextBox(buffer, 100, 150, 200);
}

Related

CP_Math_Radians

Takes an input number of degrees as a float, then returns it converted to radians as a float.

Function

float CP_Math_Radians(float degrees);

Parameters

  • degrees (float) - The angle to convert to radians from degrees.

Return

  • float - The provided angle converted to radians.

Example

void init()
{
    CP_Settings_EllipseMode(CP_POSITION_CENTER);
    CP_Font_Set(CP_Font_GetDefault(), 30);
    CP_Settings_Fill(CP_Color_Create(0, 0, 0, 255));
}

float r_degrees;
float counter = 2.0f;
void update()
{
    CP_Graphics_ClearBackground(CP_Color_Create(255, 255, 255, 255));

    // Change degrees every few seconds
    if (counter >= 2.0f)
    {
        r_degrees = CP_Random_RangeFloat(0.0f, 360.0f);
        counter = 0.0f;
    }
    else
        counter += CP_System_GetDt();

    // Print out number of degrees and convert to radians
    char buffer[128] = { 0 };
    sprintf_s(buffer, 128, "Degrees: %.3f\nis equal to\nRadians: %.3f", r_degrees, CP_Math_Radians(r_degrees));
    CP_Font_DrawTextBox(buffer, 100, 150, 200);
}

Related

CP_Math_ScreenToWorld

Takes a given set of coordinates in screen space and transforms it to world coordinates. This means that the provided position will be translated by any transformation functions called (CP_Settings_Translate, CP_Settings_Scale, CP_Settings_Rotate).

Function

void CP_Math_ScreenToWorld(float xIn, float yIn, float* xOut, float* yOut);

Parameters

  • xIn (float) - The x coordinate to convert.
  • yIn (float) - The y coordinate to convert.
  • xOut (float*) - The variable to store the converted x coordinate.
  • yOut (float*) - The variable to store the converted y coordinate.

Return

This function does not return anything.

Example

void init()
{
    // Variables to pass into the conversion functions
    float x = PI;
    float y = PI;

    // Run back and forth 100 times
    for (int i = 0; i < 100; ++i)
    {
        CP_Math_ScreenToWorld(x, y, &x, &y);
        CP_Math_WorldToScreen(x, y, &x, &y);
    }

    // Should still be PI
    printf(" %9f\n(%9f,%9f)\n", PI, x, y);
}

Related

CP_Math_WorldToScreen

Takes given set of coordinates in world space and transforms it to screen coordinates. This means that the provided position will be translated by any transformation functions called (CP_Settings_Translate, CP_Settings_Scale, CP_Settings_Rotate).

Function

void CP_Math_WorldToScreen)(float xIn, float yIn, float* xOut, float* yOut);

Parameters

  • xIn (float) - The x coordinate to convert.
  • yIn (float) - The y coordinate to convert.
  • xOut (float*) - The variable to store the converted x coordinate.
  • yOut (float*) - The variable to store the converted y coordinate.

Return

This function does not return anything.

Example

void init()
{
    // Variables to pass into the conversion functions
    float x = PI;
    float y = PI;

    // Run back and forth 100 times
    for (int i = 0; i < 100; ++i)
    {
        CP_Math_ScreenToWorld(x, y, &x, &y);
        CP_Math_WorldToScreen(x, y, &x, &y);
    }

    // Should still be PI
    printf(" %9f\n(%9f,%9f)\n", PI, x, y);
}

Related

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