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evkmimxrt1170_20_Multitask

Clear an offscreen with blue color and draw a rotating tiger on it, another rotating and scaling tiger is drawn outside, then blit them to the display that has a white background.

Hardware Preparation

If using the MIPI interface, connect the LCD displayer to J48 on the MIMXRT1170-EVK board. Connect 5V power to J43, set J38 to 1-2, and turn on the power switch SW5.

Software Preparation

Now three LCD displayers are supported, which are defined in display_support.h:

#define DEMO_PANEL_RK055AHD091 0 /* 720 * 1280, RK055AHD091-CTG(RK055HDMIPI4M) */
#define DEMO_PANEL_RK055IQH091 1 /* 540 * 960,  RK055IQH091-CTG */
#define DEMO_PANEL_RK055MHD091 2 /* 720 * 1280, RK055MHD091A0-CTG(RK055HDMIPI4MA0) */

Use the macro DEMO_PANEL to select the LCD panel you are using, the default panel is RK055AHD091-CTG configured in the display_support.h:

#define DEMO_PANEL DEMO_PANEL_RK055AHD091

For example, if your LCD panel is RK055MHD091A0-CTG, change the macro DEMO_PANEL definition as following:

#define DEMO_PANEL DEMO_PANEL_RK055MHD091

The source code is in Multitask.c, where the main function first configures clocks, pins, etc. freerots is deployed in the example. Two tasks, vglite_task and vglite_task2, are created and scheduled, to execute VGLite initialization and drawing task separately.

In addition, the tiger_paths.h file stores the path data of tiger.

VGLite Initialization

Before drawing, several functions are executed to do initialization:

  • vg_lite_init initializes VGLite and configures the tessellation buffer size, which is recommended to be the size of the most commonly rendered path size.

    error = vg_lite_init(TW / 2, TH / 2);

  • vg_lite_set_command_buffer_size sets the GPU command buffer size (optional).

  • vg_lite_allocate allocates the render buffer, whose the input parameter is vg_lite_buffer_t structure defining width, height, and color format, etc.

In the vglite_task, the second task is created, such as

xTaskCreate(vglite_task2, "vglite_task", configMINIMAL_STACK_SIZE + 200, NULL, configMAX_PRIORITIES - 1, NULL)

Once vglite_task2 is executed, its initialization part is applied first for drawing the second tiger, including functions of vg_lite_init and vg_lite_set_command_buffer_size. And a buffer array tmp_buf[3] is configured and allocated for subsequent drawing:

for (i = 0; i < 3; i++)
{
    tmp_buf[i].width = DEMO_BUFFER_WIDTH / 2;
    tmp_buf[i].height = DEMO_BUFFER_HEIGHT / 2;
    tmp_buf[i].tiled  = VG_LITE_LINEAR;
    tmp_buf[i].format = VG_LITE_BGR565;
    error = vg_lite_allocate(&tmp_buf[i]);
}

Drawing Task

In drawing task, there are following functions:

  • vg_lite_clear clears the render buffer with a solid color (ABGR format).

  • vg_lite_identity resets the specified transformation matrix, which is uninitialized or previously modified by functions of vg_lite_translate, vg_lite_rotate, vg_lite_scale.

  • vg_lite_draw performs a 2D vector draw operation, drawing input path data with the specified fill rule, transformation matrix, blend mode, and fill color, etc.

  • vg_lite_translate translates draw result by input coordinates with transformation matrix.

  • vg_lite_blit finally copies the source image to the destination window with the specified blend mode and filter mode, determining the showing of objects.

In this project, vglite_task fills the whole screen with the white color by vg_lite_clear function, and then calls vg_lite_draw to draw path data of the tiger which is rotated and scaled every time:

vg_lite_clear(rt, NULL, 0xFFFFFFFF);

for (count = 0; count < pathCount; count++)
{
error = vg_lite_draw(rt, &path[count], VG_LITE_FILL_EVEN_ODD, &matrix, VG_LITE_BLEND_NONE, color_data[count]);
}
vg_lite_blit(rt, &tmp_buf[(index+2) % 3], &mat,VG_LITE_BLEND_NONE, 0, VG_LITE_FILTER_POINT);

if (zoomOut)
{
    vg_lite_scale(1.25, 1.25, &matrix);
    if (0 == --scaleCount)
        zoomOut = 0;
}
else
{
    vg_lite_scale(0.8, 0.8, &matrix);
    if (5 == ++scaleCount)
        zoomOut = 1;
}

vg_lite_rotate(-1.5, &matrix);

vglite_task2 clears the tmp_buf[index] with blue color, and draws another tiger to it, which keeps rotating by 0.5 degrees:

// Initialize the draw.
error = vg_lite_init(DEMO_BUFFER_WIDTH / 2, DEMO_BUFFER_HEIGHT / 2);

while (1)
{
    index = index % 3;
    // Draw the path using the matrix.
    vg_lite_clear(&tmp_buf[index], NULL, 0xFFFF0000);
    for (count = 0; count < pathCount; count++)
    {
        error = vg_lite_draw(&tmp_buf[index], &path[count], VG_LITE_FILL_EVEN_ODD, &matrix2, VG_LITE_BLEND_NONE, color_data[count]);
    }
    index++; 

    vg_lite_rotate(0.5, &matrix2);
}

And then in vglite_task, the buffer tmp_buf including the tiger in the blue rectangle will be blit to the screen by

vg_lite_blit(rt, &tmp_buf[(index+2) % 3], &mat,VG_LITE_BLEND_NONE, 0, VG_LITE_FILTER_POINT);

Once an error occurs, cleaning work is needed including the following functions:

  • vg_lite_clear_path clears path data uploaded to GPU memory.

    for (i = 0; i < pathCount; i++)
{
    vg_lite_clear_path(&path[i]);
}

  • vg_lite_close finally frees up the entire memory initialized earlier by the vg_lite_init function.

    vg_lite_close();

Run

Compile firstly, and use a Micro-USB cable to connect PC to J86 on MIMXRT1170-EVK board, then download the firmware and run.

If it's successful, the correct image will show on the displayer:

evkmimxrt1170_20_Multitask

And FPS information will be sent through UART serial port continuously. The correct UART configuration is

  • 115200 baud rate
  • 8 data bits
  • No parity
  • One stop bit
  • No flow control